After having issues, I uninstalled and installed gnome-shell-extension-zorin-desktop-icons. Additionally, I had to sudo apt install gnome to boot into gnome instead of LXQt.
Now my Zorin-Pro status is gone.
I'd appreciate if someone can help me to fix this.
You may need to use your Zorin Pro LiveUSB media as a source. Insert the USB and in Software & Updates > Other tab, check the box for cdrom:[Zorin-OS...]
Now I get this error message.
The USB name is Zorin OS 16.2 Pro 64bit so I changed the name from Zorin-OS 16 Pro 64bit to the actual one via sudo nano /etc/apt/sources.list. Didn't help.
You should not have needed to install gnome - you could switch Desktop Environments from the GDM3 login screen, or the SDDM Login, if LXQT replaced it...
Even so, the command to install Gnome D.E. would have run from the Zorin Repository. It would not have removed or replaced the Pro features.