How to backup iTunes library properly?

Question

Windows

Started using Apple Music and iTunes with sync enabled via iCloud Music Library option.

It is not very clear how to make a backup of all the added songs, albums, artists, so that in which case it would not be necessary to add it all again. I'm not interested in backing up songs as physical files from Apple Music (since they can still be downloaded from this iCloud Music Library), but the list of added songs, the library structure, to then import into iTunes. For example, when you change your Apple ID or some kind of failure.

The contents of iCloud Music Library cannot be viewed anywhere online. I googled ways to export to an XML file or by copying the iTunes folder, but it's not very clear how it works in practice and what will happen in the end when restoring.

For example, is it possible to transfer all the goodness to another Apple ID in this way, if necessary?
It is clear that manually uploaded music should be backed up anyway, since when you change your Apple ID, it will not move to a new account.