Not sure if you have the same problem or not, but I had intermittent jitter spikes (and/or complete package drops) every 60 seconds on my Realtek chipset, ran:

sudo iw dev wlan0 set power_save off

And it’s been stable since (just had to make a udev rule to make it persistent across boot)

amdvlk, any reason you’re not using the Mesa driver, RADV?

… I can’t undervolt my card…

People usually use/recommend LACT for undervolting/overlocking on Linux

What is your:

1. Kernel
2. Linux-firmware
3. Mesa

Versions?

Additionally, what does the kernel logs tell you when you get a green screen?

There is a patch-series that is now merged into 6.15-rc1 that exposes more i2c/RGB controllers on the GPU side for AMD cards, so that kernel + OpenRGB (as others have mentioned) might be a solution down the line

Patch series for reference: https://lists.freedesktop.org/archives/amd-gfx/2025-January/118399.html