Whenever I go into "Full Screen Mode" in Acrobat Pro DC, the document takes forever to load with a very slow fade that debilitates my computer. I've tried adjusting settings and it happens with all kinds of PDFs, even really small file sizes. My 2016 Macbook Pro is connected to a thunderbolt display.
Hope you are doing well and sorry for the trouble. As described the application is slow when going to full screen mode.
Would you mind sharing the version of the Adobe Acrobat Pro DC you are using? To check the version go to Help > About Acrobat and make sure you have the latest version 21.05.20058 installed. Go to Help > Check for Updates and reboot the computer once.