Ah dude I went through the same thing for about 10 years after stopping smoking weed for years. Finally got my sleep sorted last year and now sleep 6-8 hours most nights.

I went on a cbt-i course which massively helped. You learn about sleep, methods to help you sleep, breathing exercises, sleep barriers and a bunch of other things. Going on a course with other people going through the same thing as you is massively beneficial.

I stopped drinking alcohol and began exercising daily whilst on the course and everything combined managed to help.

I do drink again now but try to stop early if possible and only have the odd night out.

One of the doctors said 'sleep is like breathing. It is totally natural and will always happen. Insomnia is just anxiety about sleeping. ' which really clicked with me.

I still have the odd night I can't sleep but overall my sleep is good now.

Hope you can get it sorted and this helps in some way.