Can you hotplug a GPU or do you need to still (effectively) reboot? (I know it's only the windowmanager that needed a restart but if all programs run under then, well.)
What do you mean? Switching between integrated and dedicated GPU? Or opening your case and directly removing or adding a GPU?
If its the first, I think there is support for this. There's NVIDIA optimus for NVIDIA for instance.
The second one, I never thought it could be a use case, even less that Windows would even support that. I always turn off my computer to do anything on my motherboard.
Oh yeah, didn't think of that one. Following what's written on arch wiki https://wiki.archlinux.org/title/External_GPU, Xorg doesn't support it and never will. Wayland seems to support it, but I don't know what it implies in use. The issues for KDE, Gnome and wlroot are all mergred.
