AVE10N
Do a clean OS install and do not install novideo_srgb - don't use that application at all going forward. If you need to disable dithering, use ColorControl instead - it's safer. novideo_srgb installs its own color profile in Windows, but it's unlikely that's the cause at this point.
Try a different PCI-E slot on your motherboard. It's rare, but the slot itself could be damaged. Since nothing else has helped, it's worth checking even uncommon possibilities. Also, test your graphics card on a different motherboard entirely.
Replace your HDMI or DisplayPort cable with a good certified one.
The CPU is very unlikely to be the problem - if its PCIe controller were damaged, the GPU probably wouldn't be detected at all. RAM and SSD have no effect on video signal generation, so you don't need to replace them.
Boot from a Linux USB and check the NVRAM (UEFI) variables in the terminal. Post them here. novideo_srgb doesn't normally touch those, but in theory a GPU driver could - though I've never actually seen that happen.
One important question: when you tested your monitor on another setup, did you use the same cable you normally use with your PC?
The more you focus on one unlikely theory, the harder it is to find the real cause. You're not dealing with ghosts - just hardware that needs isolating step by step.