CUPS Print Server on macOS
Enable Cups Web Interface
cupsctl WebInterface=yes
Allow Printing from Remote Machines via CUPS
Edit "/etc/cups/cupsd.conf"
Under "Location /" enable access with "Allow {ip-address}". Something like "Allow 10.1.1.0.*".
Accessing the CUPS Website
http://{hostname}:631
Adding the Printer in MacOS
Nagivate to System Preferences and click on "Printers & Scanners" then the + sine under the printers list.
Enter the hostname or ip address under the "Address" field.
Enter the printer name under "Queue" like "printers/{printer-name}".

Tested environments
Servers
- High Sierra 10.13.6
Clients
- High Sierra 10.13.6
- Catalina 10.15.2
- Catalina 10.15.3
- Catalina 10.15.4
- Catalina 10.15.5