How you can help solve it:
1) Open a support request explaining they've incorrectly banned a secure operating system with a link to https://grapheneos.org/articles/attestation-compatibility-guide with how to fix it.
2) Contact their management on LinkedIn and other platforms with the same thing.
3) Play Store review.
We have a thread with more details on the highly anti-competitive Play Integrity API masquerading as a security feature here:
https://grapheneos.social/@GrapheneOS/112878067304840664
Play Integrity API forbids a far more secure OS than anything they allow but yet it permits devices with no patches for 8 years.