I've got the exact same problem on MacBook Air M3 with Sonoma.
I even went as far a checking it wasn't a problem with the HD500X by plugging it into my old Mac (running Big Sur) and all works ok there.
Have Line6 basically dropped any support for the HD500X on any new OSs? Tried to connect to Windows 11 through parallels and no joy there either. I suspect it's a driver problem and Line6 don't care because they basically want you to upgrade to the Helix.