One additional note.
The
sticky topic for Ubuntu 20.04 users (since Pop!_OS 20.04 is a derivative) suggests installing a 'fix' for xserver-xorg-core. This is marked as a fix for xserver-xorg-core (2:1.20.8-2ubuntu2).
I currently have xserver-xorg-core (2:1.20.9-2ubuntu1.2~20.04.2) installed and did not downgrade.