I usually manage burnout by just taking some really serious alone time. Get some good snacks, watch a good movie, or play a really good game. Typically if I'm burned out, I don't want to be hanging out with other people. Sometimes I've also been known to just sit down and read for a very long time, that works too but is less common for me.
Before COVID-19 I was going to the gym 3 times a week after work. I'd spend an hour in silence in a very hot sauna every time, amazingly relaxing.
I enjoy activities like youtube, the forums, fb, etc. but they don't help me manage burnout, they kind of help me use up time between tasks and things I have to do.