Support for GA4 Properties
By default, MainWP Google Analytics Extension supports GA4 properties; however, it is required to create Universal Analytics property also. To create GA4 property is a proper way so your MainWP Google Analytics Extension can connect to it, please do the following:- Go to the Admin panel
- Click the Create Property button
- After setting basic property info, click the Show Advanced Options link
- Enable the Create a Universal Analytics property option
- Proceed to finish the property creation process.
Source Article:
https://kb.mainwp.com/docs/support-for-ga4-properties/