Yeah, I mean being able to boot either into proxmox or windows. But in proxmox, I can also open that windows install as a VM.
Some details on how it should work are here (apologies for the reddit link): https://www.reddit.com/r/VFIO/comments/aejdqk/kvm_importuse_existing_windows_install_on_disk/edqtmvb/
Framework is definitely not Linux only (laptops are Windows by default , but they offer a no-os option to install your own). They are however generally supportive of Linux, and it’s possible that they helped make the fingerprint reader firmware work well with Linux, though I have no specific information that this was the case.