I have the same issue running Big Sur 11.4 on 24" iMac M1. 2021. Also, If I select "blank screen option" screen goes whitewash ghosting articacts. I have to log out and back in to reset screen.
the only solution i have found is using the main menu option and rebooting the machine remotely.
caffeinate -u -t 2 does nothing on my system.
normal reboot works (but stinks)
logmein should fix and soon. at these prices the product should actually work.