Selfhosted

Komga is always mentioned as a good option for this. I use it for books, manga, and comics, but my requirements are quite minimal (koreader sync, opds, and mihon), so it might not work for you exactly.

I do metadata fetching using komf, documentation is a bit lacking but once setup is pretty good (I use it for both manga and comics) and it does everything automatically. There is also a browser extension that provides a UI for it. For comics sometimes I use ComicTagger for manually reviewing tags too. I would just read carefully the folder structure Komga expects if you go with that, to avoid having weird surprises :)

BookOrbit is doing pretty well for me so far with comics. Seems to have manga options about reverse reading direction.

Even better for books too. Can do koreader opds and email books as well. (I have a kobo so I haven’t tried the kindle-orientated email, but I assume it’s ez pz)

Very good metadata ingestion. And the book/comic libraries aren’t in different silo’d worlds like they are with Calibre and its derivatives.

I’m pretty pleased so far, have found some niggles but nothing bad. And the good stuff plenty outweighs anything else. It’s all ready to go, I switched libraries quickly. And it ate up my old library with its different (not as good) naming style and realigned it automatically, which was nice.

I use grimmory and have been very happy.

I really like https://vaemendis.net/ubooquity/

Audiobookshelf, Its designed for audiobooks and its folder structure is unintuitive, but it's got the best website and apps of all the ones I've tried (including kogma).

I messed around with a couple of different approaches (Calibre web, kogma, etc.), but the best all around experience I have had is Audiobookshelf. Kogma is probably better if just doing manga, but Audiobookshelf has worked the best for hosting comics/manga/ebooks. The only real annoying things is the folder structure. I've needed to use some scripts to reorganize/rename files so it handles them correctly.

I use Komga, but only as an OPDS server for Mihon on my phone and Boox tablet. I rarely actually look at the server software itself.

I haven't dug into metadata management because the files I source all seem to have good metadata, all I need to do occasionally is change out a cover image or rename some files in batches.

Yokai for manga and comics.