I'm on a Mac Mini M1 with 16GB and Big Sur 11.2.3, and am up to date on my Creative Cloud updates. About 25-30% of the time, when the computer goes to sleep, Illustrator will drop down about 1/5 of the way down the screen, as if I clicked the title bar and dragged it down the screen. When this happens, some of my panels will move around as well and I have to reset my workspace. Also, the grey space around the artboard shimmers when I move my cursor and the little popup window urging me to click and learn more about new features will have the font size reduced about 60%. All this happens with both Illustrator and Photoshop (the only Adobe apps I use regularly.) I usually end up quitting and restarting the program, and resetting my workspace. Oddly, all this doesn't happen EVERY time the computer sleeps, but it does happen fairly often, and is very annoying.
What kind of display do you have connected to the Mac mini? Do you use the "Default for display" resolution setting or one of the custom scalings? Do you have any window managers installed (Display Maid, etc)?