I actually used to run a Linux laptop + Win laptop setup with a kvm switch a couple years back. It worked just fine, but I found myself barely even using my Windows machine for anything but gaming. Eventually I found out my games ran perfectly on Linux, and ended up switching to linux on the second laptop as well, as navigating the windows desktop had become painfully clunky, lol
tl;dr: a kvm setup is great but be careful what you wish for. Once you start running Linux there is no going back…