But if you’re running a standard distro, there are guides for most them.
* Arch guide (excellent resource, applicable to all distros): https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF
* Ubuntu: https://ubuntu.com/server/docs/gpu-virtualization-with-qemu-...
* Gentoo: https://wiki.gentoo.org/wiki/GPU_passthrough_with_libvirt_qe...
You can also find countless blog posts and videos on setting up GPU passthrough.
One excellent resource for gaming use-cases in particular is this subreddit: https://www.reddit.com/r/VFIO/
Last thing to note is that your motherboard can make the process easier if it has good IOMMU support. Basically, you want a MB that puts your PCI slot in a separate IOMMU group. You can find examples by searching for “(MB name) IOMMU groups”.
Linux hosts had GPU passthrough working well before commercial software had such options. Nowadays it's just work out-of-box with Virt-Manager that just run QEMU under KVM.
It's been working for years for 99.9% of games excluding some invasive anti-cheats that ban you for VMs, but there literally only a few games that have issue with virtualization.
What do you use for the VM? Last time I checked, I couldn't find any free/FOSS VM tooling that allows me to do GPU pass-through on a Linux Host to Windows Guest.