I do understand what you’re saying - specific communities for different movies & shows. What I didn’t realize is that lemmy.film doesn’t allow community creation. If they did, that would allow people to create communities just like you’re saying.
I don’t know of any other film-centric instances, but try searching here I suppose: https://lemmyverse.net
Apologies, didn’t see the “Create Community” button up top like I’m used to on lemmy.ml, lemmy.world, etc. And I’m browsing from old.lemmy.world most of the time anyway. :P
OP, go be the change you want to see and create the communities for the movies & shows you want.