Honestly... Matrex, I believe you should reinstall Zorin OS. Something has clearly gone wrong.
If you have a 50 gig space reserved for Root and it is filled; This should not happen. That combined with other issues suggests a corrupted or broken download.
I would go right back to the beginning:
Download Zorin OS:
https://zorin.com/os/download/16/core/
Check the 256SHA
Burn to your USB using either Rufus, Balena Etcher or Unetbootin.
Then boot into the USB and install.