Much of the more mundane problem solving creativity comes from the flow of doing for me
Do you mean the task at hand guides your mind?
I've found extreme lack of sleep most useful for divergent thinking creativity, but that has attendant health issue is done too often.
I actually think that this works for me too, which is how I manage on Steem :)
Chemically induced impairment can work to, but yeah not really my thing either.
I have never tried that kind of thing, but have heard about microdosing and wonder if it is worth an experiment. Not really available in Finland, at least in my circles though.
Yes. I find just doing sets my mind up for working around things. It's technique that under pins the systematic approach to graphic design but I find it helps in many other activities too. Recent examples from me are computer programming and outdoors stuff. Basically, it's a technique for allowing tacit knowledge to contribute to problem solving without having to necessarily express whats going on in any explicit manner.
As for mind altering methods, fasting and heavy exercise can also work. Legal substances include alcohol and massive doses of caffeine - the later to the point of hallucination. I have no particular desire to try micro-dosing and have heard mixed results.
I recall Storm Thorgerson saying that drugs might make somebody creative but in his observation they make people lazy. Great to live in cool ideas land but it's just mental exercises without execution.