I bought a Made-by-AMD 7900 XTX from the AMD online store the minute they went on sale. Turned out I got a bad one - hit 110c hot spot and runaway fans in a well-ventilated case within the first few minutes playing Cyberpunk. When I saw the reddit report of AMD saying 'too bad, 110c is normal', I tried re-pasting it. It did not help - the problem persists. Then I saw the reports of AMD acknowledging the problem (thanks der8auer and others for your efforts) and to contact AMD for refund/replacement. Am I out of luck for replacement/refund because I re-pasted my card?
Personally I'd simply make the RMA claim and see how it goes. I'd say as long as you haven't caused any visible damage to the card or cooler and made a decent job, it is worth a try. The official policy however indeed is no warranty if you've tinkered with the card - that's not really legal in many countries, but you'd might threaten with a lawyer in order getting it handled.
You can also try giving them a call and explain the situation on the phone:
i watercooled my 6800xt , and had to rma it weeks after , they saw the problem was not the repaste ... you shouldn't be worried about that in my opinion as long as you didn't break anything by unmounting ... btw i saw other videos speaking about a dp cable problem, did you check with hdmi cable ? (not want to give you false hope, it's just for my curiosity)