I’m validating a social app for movies/TV — the interesting part might be spoiler-safe discussion

I’m exploring an idea for a community-first social app around movies and TV shows.
Not a tracker, not another Letterboxd clone.
The core would be:
discussion spaces for each movie/show;
user-created communities around genres/directors/tastes;
discovery through those communities;
for TV shows, discussions automatically limited to the episode you’ve reached, so spoilers beyond that point are hidden by design.
I posted the concept on Reddit and the first specific feature people reacted positively to was the episode-based spoiler control.
What I’m trying to figure out now is whether there’s a real product here or whether Reddit + Discord + Letterboxd already cover the use case well enough.
From a product perspective, what would worry you most about this idea?
Network effects? Moderation? Retention? Existing competition?
And what would have to be true for you to think this is worth building?