3blue1brown is phenomenal. It taught me how to understand a bunch of things better than studying them academically did.
“Journey to the Microcosmos” is wonderful.
ZeFrank has quite a lot of accurate biology if you want a humor channel in there.
PBS Eons is great.
I haven’t checked them out, but I feel like things like Nebula or CuriosityStream may be becoming better sources for this stuff than YouTube is. YouTube seems like it is becoming a chess, and I see no real reversal of that in the cards any time soon.