MS licensing on Sharepoint is as easy as licensing gets. It can't be more straightforward.
https://products.office.com/en-us/sharepoint/sharepoint-licensing-overview
"For On-Premises, intranet sites are licensed using a Server/CAL (Client Access License) model. SharePoint Server 2019 is required for each running instance of the software, and CALs are required for each person or device accessing a SharePoint Server."
It's that simple. CALs are requires for each person or device accessing SP. That's it. Nothing more or less. It's not just easy, but exactly what you'd logically expect the licensing to do if they were being rational.
