I tested Curtains and WindowBlinds Both are not useful for time running Windows 11 Pro. The changes in the graphical surface should be very large so the desktop modding could be heavier or partially impossible This becomes possible for the community a problem of switching to Windows 11 if you wants to continue the Stardock software use at releasing time Windows 11 in 12 weeks.
I would expect Windows 11 to be late October not the 1st October.
With regards to the apps, we would recommend people do not install Windows 11 right now as it is for developers only. You should expect compatibility problems.
Stardock are currently working on looking at compatible apps and will have information on plans for Windows 11 in the coming weeks.
I would strongly urge against the installation of WindowBlinds in particular as in my testing explorer crashed with it on.