ryans I remembered where I have seen this sort of shimmer before.. several years back, one of the Microsoft Surface tablets had that problem. I wanted to show the video of it here but I never found the link again. It was doing the same shimmering, MS had to push out a new Intel graphics driver to fix it, I don't think it was a hardware fault.
@insta42014 If you feel up to it after reading about it, can you run the Asahi Linux install script? The purpose of doing so is because not having a GPU driver, it's all software drawing. If the shimmering stops, then we know it is a software issue.. but if it doesn't, then the problem is deeper. Installing it won't remove MacOS, it just makes another partition and you can dual-boot between them.