Same. This is super frustrating.
It was happening on my old MacBook Pro and literally bought a new 16" MacBook Pro to make sure this update went well.
Downloaded rekordbox 6 and attempting to move my external USB C Rekordbox 5 library into it and it crashes (not responding) every time. All versions are updated. No good.
I've noticed if I Select the internal drive for the Database Management it does not glitch up.