I emailed them at support@greenfi.com with basically the message "I can't login I get this message, what can I do to resolve this", went back and forth a bunch, did all the annoying troubleshooting reinstalling the app, clearing app data, etc, sent screenshots of the message, assured I wasn't using a VPN, sent all the details of my phone and rom version, had to poke them when they didn't respond, got a random message of them saying "we see you were able to gain access" and I had to be like wtf no I didn't?, told them it worked if I temporarily enabled play protect and said I would switch banks if I couldnt access check deposit which is mobile only, they replied with some justification why play protect is tripping it up, so I told them that I had no issues having play protect off with other financial apps like fidelity and chase bank, and finally got a response from a "supervisor" saying "i refreshed your settings" settings" and it started working.

Not sure if they just whitelisted my account or what, but maybe if enough people complain they will get tired of whitelisting everyone and change course.