music for MAC OS 15.5 M4 keeps crashing

Some ideas:

1) Update your OS to 15.6 That may not help since I think the main difference was some security related items, but it is probably the first thing Apple would tell you to do.

2) Hold down the option key while starting Music and create a test library file with a different name. If it lets you do that then it suggests your library file is corrupt. I don't know of any way of dealing with that other than restoring your library file from a backup before all this started happening or starting again from scratch. Your media files are likely okay so you'd just be re-doing hte library file.