People are upgrading their Vbios mostly in gaming, to boost the gpu performance, especially if they are using waterblock, and all vbios got that PPT power limit kind of things.
I recently came up to vbios issue (not real issue) as I updated the vbios from ASUS official website for my 4 months old ASUS TUF 6800xt. I noticed that the VRAM "is more responsive" and drawing more power when I use the 2nd monitor, problem solved if the 2nd monitor disabled. However, one thing I noticed when I looked at Techpowerup website, my current vbios can optimised the vram more, it's capable of reading more types of vram unlike the previous vbios, for that vram utilisation, my idle if using 2 monitors goes up to 45-47'c and when using 1 monitor, goes around 40-42'c. Before that? if two monitors only 42'c max, and single monitor temp at idle averaging 35-38'c.
So BIOS of the gpu always directly related to power consumption, and, either vram or gpu utilisation. In my case that I learned, I contacted ASUS and they wanted me to return the item to get RMA done, possibly getting mine replaced but I said there's no issue apart from power draw and temp that's 2-3'c higher at idle. Apart from that, my GPU perform 3-4% better at benchmark and in game fps, so the updated bios surely does the job.
It is not directly related to your case, but I explain this to make you less worrying and maybe, hopefully, understand that you are right, this could be just vbios issue.
Gamers Vs Miners got two different goals when using GPU, and it make sense if previous owner somehow tried to apply vbios that's less power hungry, or even limit the PPT of that GPU so it will be more profitable.
If I were you? I'd keep digging deeper and deeper to find original bios and just flash it to get all default again.
About device ID? For me, you probably need to gamble here, since you gamble buying ex mining gpu, why don't you gamble it all?
Check this out
VGA Bios Collection | TechPowerUp
VGA Bios Collection: PNY RTX 3060 Ti 8 GB | TechPowerUp
VGA Bios Collection: PNY RTX 3060 Ti 8 GB | TechPowerUp
The two bios are 99% identical, only difference one allows you to put 5% more power up to 210w, and I kind of almost certain you will be okay flashing your vbios to this, but you gotta know how to do it! and if you don't know how to flash vbios from techpowerup? best ask help, may worth a dime to just come to nearest local computer store that I am sure can help you with this.
But yeah, you gamble once for getting ex mining card, now, just gamble again to fix it man. Because worst case scenario, you brick it and learn a valuable lesson, if you successfully flash it? You score and you may be able to help others facing similar issue.