Having this same issue. A workaround that just worked for me was to: Open System Preferences Click on Displays If not already selected, select Scaled under Resolution: Choose a different scaling from the one that you current have selected Switch back to your preferred scaling If previously on Default for display, re-select that option Once I switched back to Default (in my case), Mission Control started working as expected. For reference, I'm running macOS Big Sur 11.4 (20F71) on a 2019 MacBook Pro 16 with a Radeon 5500M GPU. I haven't updated to 11.5.x yet because I use this laptop for DJing and upgrading is hit or miss for support with my mixer and DJ software. Hope this helps someone. Cheers, Flux aka Andy