Just to head off the coming storm of omv 6.x on RPi questions even though I know no one will read this....
- Yes, the install script is working with the new Debian 11-based Raspberry Pi OS image - (32 bit | 64 bit)
- No, you shouldn't upgrade from OMV 5.x. The RPi Foundation recommends a clean install (read the end of the blog).
I will add more answers here as I think of them or people ask.