Question GPU problem or Display

You forgot to mention the make and model of your PSU and it's age.

Try using another display output port on your platform. Change the cable you're using to tether the panel to your GPU. Hook your panel to a donor system and see if the issue persists. Also try and use another panel on your platform to see if the issue persists. You could also try and tinker with display refresh rates and see if that resolves the issue.