>>365453679
This is true, but there's a limit when you hit a certain number of active materials in the scene that can not be overcome at all. It's a hard limit in the standard render pipeline. 
However, when you vastly reduce the render resolution, (like by opening steam dashboard) doing that calculation on the -CPU- is significantly reduced TOO because the math is done per-pixel or per poly. The same thing happens with FSR. By reducing the work to render the frame by massively lowering the resolution, you give your cpu a break and put a little work on the gpu, which is what we want here. 
It's a sliding curve though, you'll get peaks on both the cpu, gpu side: and also even the physical ram side. If your ram is low and slow, everything in vrchat slows to a crawl. 
It should be obvious that an 4k resolution is more work to process per frame on the CPU to to then pass to the gpu per material than a 1080p one. Come on. use that big brain of yours.
Many material/shader features require lots of cpu time to prep per frame. 
And yes, shaders that "bake" do help a lot.