Why isn’t my GPU turning on when I start my PC?

I'm having trouble with my setup where the graphics card seems to power up, but doesn't function at all. My specs include an ASROCK x670E Steel Legend motherboard, an 850W PSU, a Ryzen 5 7600x CPU, 32 GB of RAM, and a Zotac Gaming RTX 3080 Ti GPU. When I turn my computer on, the GPU lights are on, but the fans don't start spinning and I get no output. I can still use the onboard CPU graphics fine. Initially, reseating the GPU would temporarily fix the issue, but that no longer works. This problem seemed to occur especially when playing games, either upon startup, during gameplay, or shortly after. Despite reseating and numerous troubleshooting steps—like using different HDMI cords, dusting the system, updating my BIOS, resetting the CMOS, and reinstalling drivers—I'm stuck. I'm nearing the point of taking it to a repair shop or concluding that the GPU might just be faulty.