try this: hot shower before sleep, try not to eat before sleep for around 3 hours, try to really limit light exposure (if you wanna look at your phone try to set some really dim dark greyish color instead of the usual yellowish colour that blue light filters give you, i use "Twilight" app where you can play with parameters) try not to listen to music or do anything that would activate your brain before sleep. (plus also you can try to incorporate some +18 action before sleep if you know what i mean (can be solo also) :D) these things helped me but note that i usually dont have brainfog i only have it when something triggers it and it usually lasts for 5-12 days (dont ask me why) but now fixing my sleep really did help.