Hello,
I've just built a new PC and have the exact same problem as you:
MSI B550M Mortar Wifi
Ryzen 5 3600
RTX 3060 Ti
m.2 Slot 1 : WD Black nvme 500gb
m.2 Slot 2 : WD Blue nvme 1TB
RAM 16gb (2x8) Ballistix
BIOS ver 7C94v10 (not the latest, but the one listed against this processor on the MSI...