A way to manage a music library
I've been having issues with iTunes losing certain singles or entire albums lately, or even messing with my organizational structure. Luckily I have backups and sometimes can even go through my purchase emails to find download links that are still alive. There has to be a better way.
Don't depend on online services, other than for metadata lookup. I have a Logitech Squeezebox and run Logitech Media Server on a DIY Windows 10 fileserver. I also use MP3Tag extensively to clean up my media files. Looking at getting a Synology device and possibly switching over to that at some point. (But still running LMS for my Squeezebox at home.)
I use beets (https://beets.io/) for managing my mp3 library. If you can think of something it it can probably do it, and if not you're just a couple lines of python away.