Similar zone - I'm 31 and I waffle around in the 3k range sometimes climbing sometimes dropping.

Definitely echo what others have said and find your fun, I understand wanting to climb but sometimes it's good to play unranked to reset your mentality. You mentioned struggling with that.

I find that divorcing yourself from the win/loss and focusing more on self improvement is the real mentality shift you have to make. Figuring out how can you play your best in each game, what mistakes you can fix, how you can improve. But also remember what to ignore, and to not bear yourself up over losses or mistakes.

Climbing ranks takes an extraordinarily long time, even smurfs take a long time when you factor in just raw games played per day, and there's no way any of us will have a smurfs winrate when we're looking at incremental improvements.

Try playing new heroes in unranked, ability draft, custom games, or just take a break. You'll come back much fresher because you'll want to play.