In my country there is a support called child benefit. Basically each child gets a weekly payment to cover essentials. Great idea, popular, its not means tested, but people still complain, and on top of that it's abused. People actually have children to suppliment their income ( it's paid to the parents )
I agree with you, the key point here is it needs to be universal. The challenge is making it universal.
Though the challenge is to make UBI universal, we have to start somewhere. Any system is abused. Like our tax systems are abused big time as well. In most western countries it is the peeps earning somewhere between a lower average to the higher average salary that pays the taxes. The rich have enough means to evade taxes. Corporates, the same applies, they evade taxes. Just an example of another system that is abused.
Some peeps in my country (the Netherlands) calculated that if we would change all state benefit payments to UBI, this would save the state more money to control the current benefits program systems than the additional costs UBI will have. Obviously, we will have more peeps becoming unemployed, but they will receive UBI as well, at least those that doesn't find a new job. All this is made part of the cost calculations done by these groups.