I used:Any tricks on how to install microG?
Do you install offline or directly from F-droid?
Do you install the Services Core (com.google.android.gms) as a system app? How?
Their Prerequisites state 'Your System needs to support signature spoofing'.
flashed from recovery to install microg. After it's installed (and magisk), you'll need safetynetfix and lsposed modules:
And also install the fakestore apk. You can search for these on the first page of this thread, or in a search engine. After you install the fakestore apk it needs to be enabled in lsposed. All of that should get microg working and passing safetynet test.
The vanilla build doesn't support signature spoofing, so that's why you need lsposed and the fakestore apk to do the signature spoofing, instead of having it built into the rom.