There’s also an indev branch of Lidarr with real plugin support. I’ve been using it and https://github.com/allquiet-hub/Lidarr.Plugin.Slskd and it’s working well, although it doesn’t automatically search so it still requires some intervention. Does Soularr?
This is still fully possible on Immutable distros (which is why the name is misleading, but unfortunately is what stuck- “image-based” is a better description) and uBlue has a mechanism for it- since they’re delivered using OCI containers, it’s trivial to fork or derive from the project and add, remove or tweak whatever you need. There’s also BlueBuild which is YAML but that’s a third party project.
Blu-rays are compressed. “Zipping a zip file” doesn’t apply here because zips are lossless. Video encoding is almost entirely lossy, and there’s a lot of tradeoffs to be made between file size and quality. The whole point of the more efficient codecs is to minimize the quality tradeoff. There’s also a bunch of parameters to tune the resulting bitrate which is the #1 factor in deciding the final filesize.
That being said, I’ll agree that the least quality loss will come from using a Blu-ray remux since those are very high quality.