Just curious if you can choose Advanced Recovery option from the GRUB menu at boot time (if you have a GRUB menu at boot time - if you used EFI boot installation of Zorin, keep pressing the Esc key repeatedly at power up time. Then choose advanced options and see if booting to an earlier kernel solves the issue.
If we can get it sorted, I strongly advise you install Timeshift and setup snapshots to be taken 3 times a day - this is not cumulative - each day, 3 new snapshots replace the previous days in a cycle.
If this does not work, I strongly advise you remove the Flathub one using the Software remove/uninstall option (if available).
If APT is definitely showing then I am wondering if Snap has taken over. Zorin installs Snapd at point of install, so I strongly advise you remove Snap at least: