You are looking for guidelines and instructions to integrate SAP Marketing Cloud with Google Analytics 4 but don't find any answers on the online documentation.
SAP Marketing Cloud
This is a system limitation.
Currently it is not possible to integrate SAP Marketing Cloud with Google Analytics 4.
The current available integration is with Google Universal Analytics. You can find more details and instructions for this integration at the SAP Help links below:
GA4 integration, universal analytics , KBA , CEC-MKT-INT-GA , Google Analytics Integration , Problem