- Edited
Notafed I gave them a 1-star rating in Google Play. They apparently care very much about their rating, because they answered very quickly and opened a support case and told me to reach them via help@revolut.com with that case number in the subject.
I then sent them an e-mail, said right in the beginning that there's nothing support can do about it, and asked them to relay the feedback to the developers. Then explained the problem and sent the link to GrapheneOS attestation page, and also said that they give me no choice but to look for a different bank. I also said that this would not be a deal breaker if they provided a functioning website.
I suggest that everybody does that. If enough feedback reaches them, then we might have a very slim chance of them changing course. But I honestly don't have any high hopes (or any at all).