Big Sur 11.7.4 Permissions denied

I've loaded 11.7.4 onto my imac 14,4 gen 4 gigabyte z97. Installed on a WD black 850 2 tb nvme on a pci card. Everything went fine except I cannot change read & write permissions for the drive and therefore cannot even copy a tiny file onto the drive. get info shows - system, wheel, everyone and only system can read & write? I didn't have this problem running 11.6.5 on a regular ssd.
Anybody know how to fix this so I can use the remaining 1.75 tb on this drive?
Thanks, Al