Ok I am logged into Gnome Desktop now (and already feeling the effects of the Kryptonite...)
Clicking Zorin App Menu > Settings...
This opens Gnome Control Center.
Wifi tab on the left pane - I see my network name and a Gear Icon on the far right.
Click the Gear icon - Metered is off - At this point, I think I duplicated what you have done.
Below that is Network in the left pane. Repeating above - I click the Gear Icon on the far right and a similar window opens- Metered connection off.
IF both of those are properly set and the problem persists... please open a terminal and find your exact network name with this command:
nmcli -t -f GENERAL.CONNECTION --mode tabular device show $DEVICE | head -n1
copy that name and paste it in a gnote or notepad
then copy and paste this command into terminal replacing (NETWORKNAME) with what you copied above (no parenthesis):
nmcli -f connection.metered connection show (NETWORKNAME)
This will show connection.metered: and "unknown", "no" or "yes." You need "no."
This command will set a connection as NOT metered:
nmcli connection modify (NETWORKNAME) connection.metered no