Aur can be a bit… Wonky in my experience, sometimes stuff just fails to install or work after.

No, but you can use Ironfox or another Android Firefox fork and have working sync.

As I remember no one could tell a different in some testing done vs FLAC and 320kbps Vorbis, so I think its plenty for an archive.

Spotify uses I think 192 or 320kbps Vorbis which is quite good and still has small sizes.

Absolutely, then people go and delete the other copies leaving just the cloud, and think that it’s somehow fine.