Every app talking to microG does so using the proprietary Google Play Services library.
I also guarantee you have proprietary Google blobs such as Google Widevine DRM and Google EUICC, as the FP4 did.
I’d love to point you to the code that includes those, but /e/OS hasn’t even published source code for FP5, which is actually a potential GPL violation as I don’t even see the kernel repo.