If anyone is looking at options in this space, I used to use Media Monkey for organising and curating my large offline music collection. It did things like meta

If anyone is looking at options in this space, I used to use Media Monkey for organising and curating my large offline music collection. It did things like metadata and album art management, album-level volume levelling, and would even reorganise the file structure of your music to whatever pattern you set. I also loved that you could set up separate "libraries", so I could have metal and classical arranged by album, and EDM as a bunch of single tracks that are organised into playlists. Only downside is that it's Windows software.