It’s a mipmap issue.
The mipmaps are creating **moires pattern ** which btw happens in real life yet you get a lot of people who want games to look like the blurry post processed crap in movies.
There are two ways to fix this, lower the poly or pixel count on those parts of the mesh as the distance increases.
Or use TAA or TSR to blend past frames on the current frame.
The latter has severe downfalls being temporal ghosting and severe smearing in motion.
What happens when you use the mipmap bias CVAR and add .5 or 1?
(-1 to -15 makes textures more crisp but causes aliasing/shimmer while positive values do the opposite)
Edit: It’s geometric aliasing.