amdvbflash update
The Techpowerup thread https://www.techpowerup.com/forums/threads/amdvbflash-4-104e-for-64-bit-linux-with-updated-support-for-vbios-flash-on-big-navi2x-gpus.313927/ now have updated amdvbflash that should support Navi3x (not tested due to lack of such card).
However from my testing it dropped support for earlier Polaris=GCN4 GPUs for which flashing is actually most interesting/useful, so it maybe useful to have 2 package variants - the older for GCN-based and the newer for Navis.