"...causality would be deeply broken..."
Because of how we perceive reality, we perceive events as proceeding through time. However, as the time aspect of spacetime is a field just as much as space is a field, our perception of time as a procession of instants that each replace the other is utterly inaccurate. Conceiving of time as a whole removes the complication of chaos from consideration. While I cannot calculate - or even reasonably estimate - the sum of the involved values, I can only conceive of this gestalt being utterly equitable, and not conceive of any way in which it could fail to resolve perfectly.
The universe cannot be anything but this, IMHO. It is a whole, a unitary thing. Because time is an aspect of spacetime and therefore part of a field extending from beginning to end, just as space is part of that field extending from end to end, chaos is an illusion we perceive due to our perception of time as a directional sequence of instants. In fact the universe is a crystalline gestalt, and all factors are perfectly resolved equitably because that is the only possible way the universe can be, since spacetime is a field that is whole and entire.
"The fact that we can unify them in a more general concept does not mean the individual concepts are incorrect or cannot be taken individually to solve certain problems."
We don't unify them in a more general concept, IMHO. We perceive them very differently, and have been fortunate enough to grasp that our perceptions do not convey what actually exists, because spacetime is what exists. Neither space nor time can exist independently, except as we conceive them due to our perception of them separately. In space frozen in time, nothing happens, and in time constrained to a point in space equity does not exist (as our present understanding of quantum foam is chaotic) and only chaos exists. Only spacetime does enable reality to exist and equitably resolve, and only as a totality.
While we can conceive of space and time as separate things (in fact it is difficult for us to not conceive of them as separate things because we perceive them as separate things) GR shows that their singular existence as spacetime creates specific metrics that aren't possible to conceive unless we correctly consider spacetime as the reality, rather than space and time as separate things. The vector of anything in spacetime has the exact same value (relative to it's mass) when it is reckoned that the faster it moves through space the slower it moves through time, and vice versa. Only conceiving of spacetime enables reckoning this balance, and considering space or time as separate entities fails to reckon this equitable resolution, creating the illusion of chaos.
In just this way that vectors of mass through spacetime always balance, the whole universe equitably resolves. Chaos and the arrow of time are illusions caused by our inability to perceive spacetime as a field, whole and entire.
I reckon the appearance of chaotic eruption of virtual particles from quantum foam simply reveals our inability to perceive spacetime in which causality works directionlessly to produce the eruption of virtual pairs necessary to resolve the sum total of forces equitably. The arrow of time is an illusion produced by our perception of time as a sequence of instants rather than as part of the unitary field of spacetime, and the subsequent illusion of chaos arises from our inability to perceive reality as it exists.
Indeed, the fact of spacetime warping across time as well as space due to the presence of mass everywhen and everywhere is the essential crux of conceiving the unitary nature of reality, since that warping does not propagate through space over time, but simply exists as mass exists in the unitary field of spacetime. This is exactly like the volume of a stone does not take time to wrap around the stone, but simple exists as the stone exists. Whatever impacts the stone impacts the volume of the stone without delay because the volume of the stone does not propagate across spacetime, but is a property of the stone, exactly as the shape of spacetime is a property of spacetime. Gravity is just the shape of spacetime.
The invisibility of mass at other times effecting spacetime warping is because light moves at the speed of light, which takes time to propagate through space and thus does not affect our observations of spacetime warping due to mass present at other times because that warping does not propagate across spacetime like forces do. That warping is an aspect of spacetime itself.
Edit: I have sought to better grasp these issues and what metrics by which they can be reckoned, and have only just discovered that Hermann Minkowski has treated my hypothesis more than a century ago, in his 1908 paper "The Fundamental Equations for Electromagnetic Processes in Moving Bodies", or so I gather from the statement "From his reformulation he concluded that time and space should be treated equally, and so arose his concept of events taking place in a unified four-dimensional spacetime continuum." However, somehow in the gullywash of gibberish, it seems that despite this statement, it appears that "At a time when Minkowski was giving the geometrical interpretation of special relativity by extending the Euclidean three-space to a quasi-Euclidean four-space that included time, Einstein was already aware that this is not valid, because it excludes the phenomenon of gravitation."
I do not agree with this. It does not follow that treating spacetime as a four dimensional whole excludes gravity, and instead I see that the affect of mass reaches across time as it does space, since what the affect of mass is actually reaching across is spacetime. The whole of my speculation is that the affect of mass is acting on spacetime within spacetime, and while we see that gravity reaches across space natively, because we perceive space as a field, gravity is actually acting on spacetime and not only space, because spacetime is the actual medium. Because spacetime is a field, it's spatial aspect is a field as we perceive it to be. For the same reason, time is a field, despite we do not perceive time as a field, but perceive time as a successive sequence of instants. Time is not a successive sequence of instants. There is no arrow of time.
The arrow of time is an artifact of our imperfect perception of spacetime (and perhaps of mathematical description, which I am incompetent to address, since I have no comprehension of how spacetime is described mathematically), and specifically of time as a sequence of instants succeeding one another. In fact time and space aren't actual separate things but are both aspects of spacetime, which is a unitary whole that extends entirely from such beginning to such end as exist in the universe, a continuum warped by the presence of mass.
Given that mass warps spacetime, it follows that mass we observe as well as mass we do not observe in our imperfect perception of spacetime is effecting that warping, because while we perceive mass in a present instant, mass actually exists in a continuum, not a sequence of instants succeeding one another. Exactly as we see that mass a meter from a point of observation effects spacetime warping, and mass 10 meters away effects spacetime warping, moderated by the inverse square law, mass 1 second from the moment of observation effects spacetime warping, and mass 1 week from the moment of observation effects spacetime warping, moderated by the inverse square law.
I cannot grasp that mass cannot effect spacetime warping across the spacetime continuum when the difference from the point of observation is delay rather than distance, which gravity does reach across. If gravity does reach across distance it is also reaching across delay, because what it is reaching across is spacetime and every distance necessarily includes delay. Delay cannot exist without distance, nor distance without delay. Both are actually aspects of what mass exists in and affects, and do not exist otherwise.
Mass cannot cross space instantly. It always takes time to cross space. This is why what mass is crossing is not space, but spacetime. However gravity does not cross spacetime. Gravity is a feature of spacetime. Gravity does not take time to exist. Time is an aspect of spacetime just as is gravity. The shape of spacetime is gravity.
Mass warps spacetime. It is this warping that is called gravity. This warping does not cross space over time, because what is warping is spacetime. This is why I say gravity is not a force and does not propagate across spacetime like light or other forces do. Gravity is the shape of spacetime itself, and thus does not propagate across spacetime. Gravity is the form of spacetime, it's nature, like the volume of a stone does not take time to form around the stone, but simply is an aspect of the stone, gravity is an aspect of spacetime.
However, when mass is moving in spacetime, the warping of spacetime moves across the continuum as a result of the movement of the mass and at the rate of movement of the mass, because the mass effect is moderated by the inverse square law, and is not effected without moderation, so the shape of spacetime changes at the speed of the movement of mass. This is why when the ripples of spacetime warping proceeded across the spacetime continuum when two massive black holes collided, which we detected in 2017, they moved across the continuum at the speed of light.
That speed of the movement of the ripples was not the speed of gravity, but of the pressure wave produced by the collision of masses that cannot move or interact faster than the speed of light, which collision speed is not gravity anymore than mass is gravity. The collision of the black holes changed the warping of spacetime turbulently as the collision was not smooth, but turbulent. This turbulence produced the pressure wave, and the speed of the turbulence is the detected speed of the ripple across spacetime, not the speed of gravity.
Gravity has no speed, just as volume has no speed. Gravity is an aspect of spacetime, just like space and time. Speaking of a speed of gravity is the same as speaking of the speed of space, or the speed of time.
While I have utterly no ability to understand any of the relevant math, I am told by @Shaula on Cosmoquest that the affect of "a mass 1 second away in time would have a gravitational effect 30,000,000,000,000,000x greater than a mass 1m away. So you need to introduce some scaling factor for masses displaced in time to counter that - and if you make it 1 / c^2 then the effects rapidly become unmeasurable. If we use that scaling then an object would need to be almost stationary for about 300x the age of the universe to experience the same effect as having a similar object a metre away."
It makes no sense to me that the stated calculable affect is 3x10^16 larger for a mass 1 second removed from the instant of observation than a mass 1 meter distant, and should be reduced by some factor, and particularly a factor that so reduces it as to require it to exert it's affect for 300x the age of the universe before it compares to a similar mass a meter distant. It seems to me that somewhere something is being reckoned wrongly, since both scales mentioned are outside of reasonable consideration. As I do not have, and never expect to, the ability to so reckon I guess I am just grateful that I have glimpsed something my betters have considered.
Further, I am unable to find any recent incorporation of this seemingly necessary recognition that spacetime is affected by mass in Hermann Minkowski's four dimensional continuum, and find instead that dark matter is introduced and no affect of mass elsewhen is reckoned at all. Since mass cannot affect across distance without also affecting across delay, I am baffled. I am further baffled at the contention that the shape of spacetime is claimed to take time to propagate, that there is a speed of gravity.
I am left humbler, if more mystified, and with a deeper appreciation for your kindness in spending time in discussion with me.
Thank you.