Problem is - I have no idea what to do about it.
It's so hard to do anything fun in my free time because the moment I think about doing / starting something, goal oriented t thoughts follow, which means stress follows.
I wish I could just go into "kick the can" mode whenever I wanted and turn off the part of my brain that wants to see results, progress, and checkmarks.
Maybe you have absolutely no desire to be a painter or artist. Pick up a pencil and just doodle for 30 minutes. Get some cheap paint and a small canvas on your way home from work and just spend an hour going for it.
Maybe you've always wanted to try fencing. Find a place and take a couple classes just to see what it's like.
I'm also like that, anything I start as a side project almost immediately becomes "if I don't change the world with this, why am I wasting my time?" So I had to start doing things that I know will never amount to anything, and specifically tell myself "This will never matter." When you can accept that you're spending a little time on something that's just for its own sake, then you've done it - you're experiencing an honest-to-goodness leisure activity.