I handed in my 3-month notice recently and have to take the rest of my vacation days and overtime before October. That amounts to about a month, although I'm not taking all of it in one piece.
I have booked a 5-day beginner course to learn Windsurfing for the end of the month, plus I warned my boss that for the month of August, I'll be taking days off whenever the waves look good. That's my dedicated "touch grass" hobby for this time period.
Other than that... I have a lot of programming stuff I want to learn, but only because I already program a lot. Zig and htmx are at the top of the list right now, but if I find the motivation I'll be dabbling in Django and Angular as well (need them for my next job).
Otherwise, I'm not stressing about being productive or acquiring any "useful" skills. That kind of "constant self-improvement" mindset just doesn't mix well with my existing burnout. Just surviving is a good enough goal imo
Also don't forget that all horses officially have their birthday on January 1st. So when celebrating the new year, you are obligated to say happy birthday to all the horses.