>> Fandoms could be something like various video games, movies or manga (Genshin, Hazbin,... well, many). <<

That sounds like a fun mix.

>>I'll probably have things like icons, fanart, meta, recommendations/reviews, q&a memes and video game screenshots.<<

That combination should attract a wide audience. There are lots of review and recommendation communities where you might crosspost sometimes. For meta, watch out for marchmetamatterschallenge.