Cant believe it, 3 years later... I have the same exact problem as mentioned above.
I've followed the rabbit hole, and I also got to the same conclusion, that I need a newer VBIOS for my card.
I looked up all the details on my card, and I'm fairly certain I have the exact same card as OP here.
The issue is that my build date for the NVIDIA BIOS is 2020-11-26, so it's too old. But the nvflash wont update to newer versions it seems, and if I try to use the regular installer I will get the same message that I dont need to update it... But yet I do! And yes, double and tripple checked that I have enabled ReBAR in BIOS top right corner as well. 110% sure I have the same issue.
Screenshots from GPU-Z below:
View attachment 318506View attachment 318507View attachment 318508
Any help would be appreciated at this point, as I am going nuts here... So annoying.