Exact GPU Model: ASRock Radeon RX 5500 XT Phantom Gaming D 8G OC (90-GA1NZZ-00UANF)
Some nice high-resolution PCB photos: https://www.techpowerup.com/review/asrock-radeon-rx-5500-xt-phantom-gaming-oc-8-gb/images/front_full.jpg https://www.techpowerup.com/review/asrock-radeon-rx-5500-xt-phantom-gaming-oc-8-gb/images/back_full.jpg
Either use thermal adhesive to glue RAM heatsinks to it, or directly machine it out of copper and do fancy custom heatpipe/watercooling stuff from there.