eta: also I struggle with this too :') medication generally keeps the brain fog away but then I just get caught up by task paralysis, do something else, and then end up ruminating + getting anxious about the things I should be doing/should've done.
over the years I've found things that help occupy + quiet my mind enough for me to get sleepy, usually methodical things like sudoku, solitaire, paint by number, etc. I almost always have youtube or a twitch vod playing quietly in the background to occupy my auditory attention