Yeah, there’s generally more damage from thermal cycling than sustained heat on modern electronics. I guess the fan bearings would be closer to end of life? Shouldn’t be a huge concern.
I’m generally really in to super efficient hardware, but just based on TDP vs other specs I think most of the efficiency gains in the 2080 are probably from the move to GDDR6. That’s nice but not something that I’m going to drop that kind of money on, especially if there’s piles of 10 series cards from retired miners floating around.