Debian Buster (which is "stable" now) defaults to Wayland in Gnome, but you can switch to Xorg at the login window, which I had to do this week for screencasti

Debian Buster (which is "stable" now) defaults to Wayland in Gnome, but you can switch to Xorg at the login window, which I had to do this week for screencasting to work as expected.