I was in a similar position to you. I had 500k karma iirc and I was legit addicted.
Delete your account. That's what I did. It was unthinkable and honestly kind of painful but looking back I'm so glad that I did. Rip the bandaid off and you'll never really have a reason to go back.
Find a Lemmy app that you like (or mbin or kbin, they all serve the same content (kinda)) and just use that.
Lemmy has far less content so when you run out of things to look at, realize that that is the addiction and try to do anything else.
When commenting, try and remember that you're (probably) responding to a real human and don't be an asshole. Admittedly I'm not always great about this but have made a lot of progress in the right direction.
Try not to get involved in the inter-instance drama. It isn't worth your time.
Its a process. You're going to find what works for you. You'll probably fail a bunch too but life is about getting back up when you fail so just keep at it and you can make meaningful change if you want to.
Completely, if you look at tiling window managers.
If you're a gnome user check out PaperWM as well as Search Light (which is like Spotlight or whatever its called on Mac).
And Vim really is that good. I started using it a few years back and I can't imagine using anything else. There's a bunch of Vim alternatives, like Helix or NeoVim if you want to explore.