it is annoying that it can't remember it by series. Perhaps for a normal series I don't want captions but for a foreign language one I do. Perhaps for a foreign language that I'm good at I don't want it, but for others I do. Perhaps for a foreign language that I'm learning, I want it in that foreign language (ala english for english content) but dont want it for others.

Global "works", but remembering by series would be so much better.

It's dumb the apps don't remember that, but I think it's not nice that you're being downvoted for neutrally pointing out a workaround.