Final post on this matter:
These challenges are ultimately down to a combination of rootless Xorg (X11), udevd, virtualization software, and a somewhat crude polling strategy in libdrm. Fedora Linux is affected because the way the distribution has been set up - but the exact same challenges apply to, say, OpenSUSE and Ubuntu.
To scratch my personal itch, I have created Accelerate device open on rootless X11 · shoffmeister/drm@db85c9d (github.com) - and once you notice that the commit message is massively longer than the straight-forward change itself, you’ll either tune out or be totally pleased that this enables you to restore a lovely responsive X11 desktop environment under virtualization.
This is kept under Commits · shoffmeister/drm (github.com). I am not sure whether I will maintain any of that, as I do hope that KDE will start working well on Wayland and VMware Workstation in the near future.