I do not see how to import sources

You need to install extensions before you can use the source section to perform a search. Once you've done that, typing something into the search field under sources will search through all the extensions you have installed.

even a local one

They have an entire guide on that.

I haven't ever tried it so unfortunately I can't directly compare. I've been using kodi + debrid for years though with zero issues, and since it served my needs perfectly I haven't tried anything new since. I even set it up on a chromecast for my tech illiterate dad, and he's been cable/stream service free since.

For Manga/Comics/Webtoons/Etc.:
Tachidesk on desktop
Tachiyomi on mobile.
These are both fantastic and allow you to grab manga, comics, etc. from pretty much every site you can think of to have it all in one place.

For Movies/TV/Anime:
Kodi + Debrid + Arctic Horizon 2/TMDbHelper + Fen + Otaku (resources: 1, 2; screenshots: album)
I love this. I can watch literally anything I want as if it was a netflix-like service, and don't have to use a VPN. Can even throw this on a shield/chromecast/firestick.

edit: tachidesk doesn't have a fit-to-page feature, but you can just use stylus with this:
img{
height:100vh !important; /* fit height of screen */
min-width:0 !important; /* also needed for fit height */
}
edit 2: Also, not really piracy per se, but Syncplay is great for watching downloaded content with friends.

The fishnet thigh-highs and garter straps from this angle👍