Not in the way that Windows does, at that point your best bet is SysRq+REISUB or SSH in and kill kwin and possibly issue a manual reset in /sys. But even if successful, half your apps will have died as Wayland compositor handover isn't quite reliable yet.
I also believe if the GPU hangs the kernel already tries a reset, I would start with a manual reset via SSH to confirm it's even worth pursuing and then you can figure out a hotkey situation. Even if the GUI is locked up, you can listen to evdev devices and catch an arbitrary keyboard shortcut and run a shell script that resets the system to your liking.
I'm not sure what problem you are encountering exactly, but switching to another virtual terminal might still work.
By default, the virtual terminals are linked to the F1-F8 keys, and the combo to switch from a graphical session usually is CTRL+ALT+Fx.
On that other virtual terminal, you might be able to kill KWin.