AlphaElwedritsch Would these apps that require Google Play integrity run if you installed Lineage OS with full GAPPS? Would the GAPPS work around the problem, or would that not work either?
If it is secure attestation, the signed attestation would either include information that it is running on Lineage OS, or would not have a valid signature. I don't think it is likelier that Google is accepting valid attestations made on Lineage OS than valid attestations made on GrapheneOS for their Play integrity service.
The key point is that you cannot hide what device you have, what OS you are running (OS version and signing keys), or what app you have installed (app version and signing keys). This is for attestation in general, I assume it is the same for Google Play Integrity, but I don't know anything specific about that.