Regarding the iTunes suggestion from above, I’ve mentioned before about using the Retroactive app to install older versions of iTunes such as the one I use which is 10.7 CoverFlow and it does work on Sonoma with a few caveats which I posted a few weeks ago:
I don’t know what Mac you’re using but I’ve installed iTunes on an M1 Air running Sonoma and also on my older 2012 Mac Mini running Sonoma (previously Ventura and Big Sur) using Open Core Legacy Patcher. It’s possible that it could help you recover some of your missing files since you probably purchased them when you had iTunes and maybe you could use them later in the Music app. I don’t use Music since I’m still happy with iTunes but I suppose that eventually there will be no way to use it on newer OS’s. Once a stable version of Sequoia comes out, I will upgrade and see if iTunes will still run under that system.
EDIT: I should add that besides 10.7, you can also choose from iTunes 11.4, 12.6.5 or 12.9.5 but I’ve only used 10.7 primarily.
Here is an article regarding the Retroactive app: