See https://privsec.dev/posts/android/banking-applications-compa... for banking apps. Anything that's not a banking or government app is extremely likely to work. Very few other apps ban using a non-Google-certified OS and that's the only significant reason for incompatibilities. GrapheneOS has a per-app exploit protection compatibility mode to work around memory corruption bugs caught by the features. It's in the process of overhauling the secure spawning feature to avoid tripping rare anti-tampering measures in certain banking apps. Play Integrity is increasingly the only compatibility issue. Some apps using Play Integrity have explicitly permitted GrapheneOS though.