I've been doing what limited testing I can in a virtual machine environment, but so far Windows 11 seems to be causing far less symptoms than Windows 10. It's still the same awful Win 10 user interface, but it is causing almost no symptoms, eye strain, or migraine when looking at it.
Oddly enough, when you disable the visual performance settings in Windows 11, the display actually seems worse, where in Windows 10 that helped. That would lend some credence to my dwm.exe theory since those settings are all directly routed through the dwm.exe
I took a snapshot of the dwm executable in Windows 10 and Windows 11 and it is certainly different, almost 20% larger and a build date of 6 months later. And it makes sense since Windows 11 has many more visual effects and they all would be controlled by dwm.exe
Windows 10 DWM.exe
Windows 11 DWM.exe
I should mention that the version of Windows 11 I am running, while advertised as the latest Insider Preview build, does not seem to be using a lot of the new graphic interface features besides the start menu. For example my Settings menu look exactly like Windows 10 not like the new one all the screenshots say Windows 1 should have.