Whenever i search for some somewhat obscure videos, like for an uncommon bass guitar or a highly regional dish, i get recommended horrible videos because the algo gets bored or gives up?

I think that the algo works by spotting correlation patterns in a "people who watched x also watched y" kind of way, so if you're looking at something really obscure, small aberrations and maybe even individual histories can distort the resulting recommendations because it just has fewer accounts to pull from. Just speculation.