I got these!

Hopefully if I can get my hands on a 3080 and 3090 I’ll be able to test the sizes out on them as well but sounds like a bit before I can do that lol

I just changed my gigabyte card and it worked. I now get 98 MH/s and memory temp only goes to 90c -92c as oppose to 102c - 108c. Core clock at 200, mem clock at 1200 with 62% power using 230W. That backplate is hot though like you said. I only had to use these thermals below as it was enough to change out all the thermals on the chip and more enough for the backplate.

https://www.amazon.com/gp/product/B08GQQ7CZR/ref=ppx_yo_dt_b_asin_image_o04_s00?ie=UTF8&psc=1

Also I had to change all this while the fan power cords were still plugged to in to board since it was impossible to unplug them. I thought I broke it trying to pry those plug out. I just left them on and had to add these pads the hard way. It was rough but I managed to get these pads in.