I'm using an RDNA3 GPU, too, and don't have that problem.
Did the problem start after you began undervolting/underclocking?
A quick web search for rdna3 "green screen" turns up results. In at least one person's case, the problem turned out to be their power supply.
If you want help, you might want to share your:
- linux distro
- kernel version
- AMD firmware version (e.g. firmware-amd-graphics package on Debian)
- Mesa version
- whether Steam or Flatpak are involved (because both can affect Mesa)