Wonder if the info you found out about games using AVX was (very) specific to the AAA titles you tested/played or was it more general about games using AVX etc? For about 1 year, I dual-booted my cMP with macOS 11.x.x/12.x.x and Win 11 using first an RX 580 and then RX 5700 GPUs. I used to game regularly on Win 11 with titles like Red Death Redemption 2 and Cyberpunk 2077 at 1080p -- with graphic settings pretty much maxed out and never had an issue at the time. Frame rate was pretty good for the cMP (although neither of those GPUs have Ray Tracing so never used that). You can read more on these gaming benchmarks
in this thread. Anyhow, still a bit unsure about what is causing your issues with gaming, but my gut feeling is that there might be something other than AVX at play?