Volen do something to help you guys to get GOS attestated?
Unless a number of things change with their requirements its unlikely Google would ever certify GrapheneOS see https://discuss.grapheneos.org/d/10712-what-are-stoppers-of-grapheneos-becoming-a-google-certified-os/7
Currently Play Integrity, as used by apps, does not provide useful security guarantees about the OS for the app. The OS can be very old and long out of security updates.
Very few, if any, apps use the more strict hardware backed Integrity so it is possible for an OS to spoof Integrity, presenting itself as another OS/device that passes. Google are cracking down on spoofing by denying Integrity passes for OS/device identities that they have discovered are being used by spoofers.
cdflasdkesalkjfkdfkjsdajfd What other apps will be blocked besides banks?
It is only apps which feel there is some kind of security benefit to them for using Play Integrity and if the app developer looks at how Integrity works they will see that there is very limited or no benefits to them and instead disadvantages. There have been very few apps besides banking apps using Safetynet or Integrity and it is highly likely to remain that way. A number of apps that started using Safetynet dropped it and havent switched to Integrity.
A small number of app developers are confused and mark their apps on Play Store as using Integrity but dont actually have it implemented within their app. These apps will run on a device which doesnt pass Integrity.