I came across this thread and the original repo trying to get an HP Microserver Gen 8 working; here's the compiled binary for 5.11.x (and repo fork if you want to compile yourself)
I've updated the build scripts to work with proxmox 7, but the kernel snapshot shortcut doesn't work for
hirsute yet, so it takes a lot longer to compile (but functionally identical)
The original idea behind the patches still work, just the sources for 5.11.x is slightly different so the diffs need to be recalculated. There's also a patch_notes.sh roughly outlining how to generate the .patch files for the 3 modifications for any kernel
https://github.com/crankswagon/relax-intel-rmrr/releases