Used to dual boot, but with the combo of steam/proton and VFIO passthrough + looking glass, it’s been really solid to just run both at the same time. File sharing between the two is pretty easy in that case, because it’s just the usual rsync/scp tools or SMB share.
Although, I’ve found I very rarely need the guest for gaming anymore, more so for opening the odd Photoshop file and similar tasks.