I struggle with this too.
Until recently we tended to rehearse until about 10.30ish, and I’d be home about 11, but it was always difficult to sleep afterwards, and after a gig I’d be in around 1am, but wouldn’t be asleep until 2.30/3am. I generally have to sit down, maybe watch some tv or read a book for half an hour or so.
I think it’s in part the adrenaline from performing, and then the quite stressful load outs too.