I can't tell if this is actually a new project or if you forked, extended, and changed the license of an existing MPL 2.0 project. The latter would be a bad thing.
You have a commit titled "Full rewrite!!" but I'm not about to go do a comparison to see how "full" it is. If it is indeed a complete clean reimplementation then I would recommend making it a new project so it doesn't look like you took someone's FOSS code and relicensed it for yourself.
This started as a fork but was fully rewritten from scratch. No code is used from the original repo, so I also chose to make the license more premissive.
You have some good points but if I made a new repo from scratch, it would break many links, including links in the add-on's store page, the add-on itself and search engines. It would also kill every watcher/issue/PR etc so I don't think it's really a good idea.
If you have a clean solution to solve this I'd love to hear it!
After looking it up, yes it's a bit like IDM (Internet Download Manager) but has less features (like it's not separating which files are audio, video... yet?), however it's available on mobile as well so there's that