Filterable post flairs and instance-agnostic links are my two biggest wish list items that I think would go a long way to making that specific community much nicer (speaking as a mod).
The project relies on extensions that are installed separately to pull content from different services (mangadex, mangaplus, etc.). The other day, the tachiyomi devs removed almost all the extensions that they were hosting/maintaining after a threat of legal action from a Korean webtoon company. Here is a relevant discussion thread.
Here is a guide to a third party extensions repo that was linked in a discussion thread the other day.
I haven’t personally done this with my Tachiyomi yet, but have heard from others it has worked well.
This is an excellent point that I thought about when a previous community I was active in got shut down on the ml instance due to some admin whims. Since then, for the two communities I run, I have an external wiki that I maintain with things like complete rules or an index of past weekly discussion threads, etc. These wikis are set up on a VPS that I am responsible for, independent of the host instance of my communities.
ani.social and the admin, @hitagi@ani.social, has been excellent, and the instance is a logical place for anime/manga communities. I have also tried to keep up donations to keep the server running, but people’s lives change, not always by choice. Having some form of communication independent of the lemmy instance makes sense for those scenarios, if for nothing else except for communicating a migration to a different instance.