I’m a light sleeper with a loud mind, as well, so this kind of thing has always been a problem for me. The two main things I find helpful may not do the trick for you, but here goes:
First, trying to force myself back to sleep always just ramps my brain up worse and makes it more difficult than it already was to fall back asleep. I stopped trying to force the issue, which has counterintuitively sped up the time it takes me to fall back asleep. I don’t get up or engage my mind with anything significant, but if I’m awake, I’ll put soft music on my earbuds or scroll on my phone set to the dimmest setting. I may not fall back to sleep immediately, but I’ve found that lowering the pressure on myself to fall back asleep makes it happen more readily than when I spend 2 hours and 45 minutes being like “if I fall asleep right now, I can still get another 3 hours. go to sleep. fall asleep. sleep will happen… now!”
Second, I’ve increased my oversell magnesium intake. I know you said no substances, but I feel like this is different. There have been a few studies–popular science type stuff, nothing peer reviewed that I know of–indicating that magnesium improves sleep quality and the ability to return to sleep if woken up. Might be the placebo effect, but I don’t care because I’ve noticed an improvement.
Sorry you have to deal with this flavor of insomnia, too. Super sucks.
Nanny state foolishness. It’s just crewed spaceflight, not rocket science.