Well sadly this was to be expected in a way .....
Drastically reinstalling the D-E solves the problem ...
But first you could try via the settings manager (opened as sudo then) to delete your inlog-account and create a fresh new account (user I mean) granted ALL administrators rights ..... Not 100% shure it will work, but you can try it at least as first step. Why ? It works in sudo , so it should work as user as well .... and it could be the permissions in the users account is off-set.
Drasticly installing the D-E is a 100% good method I guess.
sudo apt purge zorin-os-desktop
sudo apt install zorin-os-desktop -y
Don't forget to make a brand new administrators account or a users account with admin's rights. You could break the entire system on doing this little D-E reinstall.
At the other hand ....... Why not FRESH install a brand new Zorin Core OS ? I think this will give for you the least of problems after the changes you make.
Zorin can be installed again as many times you want, there are no restrictions involved like this is with Microsoft's Windows. Don't forget that good aspect of Linux. We all had this on our hands in the beginning days of Linux lol ..... no shame, no game lol