I wonder if this sort of thing can lead to faster burnout or such. I've sorta over time leaned toward guarding my own space/time since somehow I get more tired out, and over time more burned out, if I don't.

I probably have a very similar "dysfunction" as OP. Can't say how it is for him, but I do get burned out somewhat regularly if I push myself too much for too long. However it usually takes few days to a week at most of low-effort activity or travel to recover.