I use tubifarry, a lidarr plugin to use slskd (soulseek) to find and download albums. For me is way better than searching for torrents

I don't think there is anything, really. I use a soulseek client to get flac files and convert them to opus manually.

Radarr and Sonarr work because the naming conventions for videos are more or less established.

With music, everyone has a different philosophy for tagging, renaming files, transcoding, how to handle best-of albums, compilations, etc. So what works for you probably doesn't work for me and vice versa.

Lidarr gets very few updates, I don't think anyone is working on it anymore. I remember the problem was keeping up with metadata handling.