Here are the Play Store pages where you can leave feedback:
https://play.google.com/store/apps/details?id=com.revolut.revolut
https://play.google.com/store/apps/details?id=com.revolut.business
Ask them to use the Android key attestation API to perform attestation with the ability to permit GrapheneOS. We linked our guide on using it above and it works well.
@GrapheneOS I found this reply on the reviews:
> [...] To protect our users and ensure compliance, we implement measures to limit access from devices with custom firmware. This is primarily to safeguard accounts against potential vulnerabilities that can arise from altered operating systems.
That's very generic, and (especially when the review in question mentioned the security benefits of GrapheneOS) very telling.