KVM is indeed a type I hypervisor and will be the best performing. I think VMware uses KVM under the hood. As far as graphics goes it works fine.

Virtual box is slow and doesn't perform nearly as good as KVM because it isn't native. The benefit of Virtualbox is that it runs on anything. I also should point out that KVM can run as a Type II in some cases if hardware acceleration isn't present.

Are you speaking from recent personal experience? I run a lot of virtualization in both my homelab and my laptop. KVM runs very fast and has no slowness. I can play games in it (with some tweaks) and I rarely install anything locally. I use flatpaks, containers and VMs. Even when Windows 11 is running without 3D acceleration it still is snappy and smooth. You just need to install the Virtio drivers from the Fedora project. If you don't you can't copy and paste and the performance is degraded. I am saying this all from personal experience. I have seen a lot of people call KVM a type II which is simply not true in most cases. At the end of the day it is a grey area but KVM is pretty much what powers the cloud. It is what AWS and other public cloud providers use.