Same issue with proxmox 6.2/6.3 on two Servers. Both with:
Supermicro X11SSH-F / Xeon E3-1220 / 2x 480GB Samsung SSD.
A "zpool import -N 'rpool'" does not work, because there are no zpools available.
Installation on a single Disc does not work either, because of the same error above.