What file system are you using? It may be snapshots... if so, do a backup (or preferably clone the drive to an external drive), then clear the snapshots.
Then list the installed package sizes and determine which you don't need, and sudo apt purge them (if you see it trying to uninstall any dependencies that have 'Gnome' or 'Zorin' in the name, cancel the process, as continuing will likely bork your install).
aptitude search "~i" --display-format "%p %I" --sort installsize
If you want to list all packages and all their dependencies and reverse dependencies:
for packages in $(sudo apt list --installed 2>/dev/null | awk -F '/' '{if (NR!=1) print $1}'); do sudo apt-cache depends $packages; sudo apt-cache rdepends $packages; done
--or (if you want the list saved to a file)--
for packages in $(sudo apt list --installed 2>/dev/null | awk -F '/' '{if (NR!=1) print $1}'); do sudo apt-cache depends $packages | tee -a /home/$USER/Desktop/dep.txt; sudo apt-cache rdepends $packages | tee -a /home/$USER/Desktop/dep.txt; echo '-------------------------' | tee -a /home/$USER/Desktop/dep.txt; done
... but keep in mind it's going to be a long list and may take a bit to run.