I'll admit that I forgot grapheneos was android, but the devs (at least as of a year ago) said it wasn't supported and that that was intentional but didn't say why. The IT department at my company also said grapheneos isn't supported by it.
The app is RSA Authenticator (SecurId). If someone is able to download it and make sure it launches I would appreciate it so I can try to make the switch finally. It's an awful app in every way though, just look at the comments
Other comments on the app also say it doesn't work on rooted devices since it scans the other apps you have installed and won't work if it finds something it doesn't like. Garbage app that is one of two of the required 2fa app for my work for some awful reason. (One is a normal, god fearing 2fa used for account sign ins. The problem one is used for accessing the company VPN) It generates 8 digit auth codes and the "token" to add it was a URL instead of just a string of characters so I can't just use another app