I'm not risking logging out on my device to confirm that but I heard that Revolut isn't using Play Integrity API but rather DexProtector/Licelus. They have this demo app https://play.google.com/store/apps/details?id=com.dexprotector.detector.envchecks
I ran it with logcat open and I haven't seen any logs from Play Integrity (not sure what to expect, I remember that SafetyNet would show results in logcat). Perhaps it would be easy to spoof on OS level whatever this thing doesn't like? I can see in logcat stuff like
12-08 23:28:40.826 22793 22793 I com.dexprotector.detector.envchecks: MMAP_TRYLOCK is supported in uffd errno:2 addr:0x6bd2ddd000 size:4096
12-08 23:28:40.827 22793 22793 I AndroidRuntime: Using default boot image
12-08 23:28:40.827 22793 22793 I AndroidRuntime: Leaving lock profiling enabled
12-08 23:28:40.827 22793 22793 W libc : Access denied finding property "odsign.verification.success"
12-08 23:28:40.827 22793 22793 W libc : Access denied finding property "ro.debuggable"
12-08 23:28:40.828 22793 22793 E cutils-trace: Error opening trace file: No such file or directory (2)
12-08 23:28:40.940 22793 22793 W libc : Access denied finding property "ro.product.name_for_attestation"
12-08 23:28:40.940 22793 22793 W libc : Access denied finding property "ro.product.device_for_attestation"
12-08 23:28:40.940 22793 22793 W libc : Access denied finding property "ro.product.manufacturer_for_attestation"
12-08 23:28:40.933 22793 22793 W main : type=1400 audit(0.0:106100): avc: denied { read } for name="u:object_r:build_attestation_prop:s0" dev="tmpfs" ino=181 scontext=u:r:untrusted_app:s0:c18,c257,c512,c768 tcontext=u:object_r:build_attestation_prop:s0 tclass=file permissive=0 app=com.dexprotector.detector.envchecks
12-08 23:28:40.940 22793 22793 W libc : Access denied finding property "ro.product.model_for_attestation"
12-08 23:28:40.933 22793 22793 W main : type=1400 audit(0.0:106101): avc: denied { read } for name="u:object_r:build_attestation_prop:s0" dev="tmpfs" ino=181 scontext=u:r:untrusted_app:s0:c18,c257,c512,c768 tcontext=u:object_r:build_attestation_prop:s0 tclass=file permissive=0 app=com.dexprotector.detector.envchecks
12-08 23:28:40.940 22793 22793 W libc : Access denied finding property "ro.debuggable"
12-08 23:28:40.933 22793 22793 W main : type=1400 audit(0.0:106102): avc: denied { read } for name="u:object_r:build_attestation_prop:s0" dev="tmpfs" ino=181 scontext=u:r:untrusted_app:s0:c18,c257,c512,c768 tcontext=u:object_r:build_attestation_prop:s0 tclass=file permissive=0 app=com.dexprotector.detector.envchecks
12-08 23:28:40.933 22793 22793 W main : type=1400 audit(0.0:106103): avc: denied { read } for name="u:object_r:build_attestation_prop:s0" dev="tmpfs" ino=181 scontext=u:r:untrusted_app:s0:c18,c257,c512,c768 tcontext=u:object_r:build_attestation_prop:s0 tclass=file permissive=0 app=com.dexprotector.detector.envchecks
12-08 23:28:40.933 22793 22793 W main : type=1400 audit(0.0:106104): avc: denied { read } for name="u:object_r:userdebug_or_eng_prop:s0" dev="tmpfs" ino=448 scontext=u:r:untrusted_app:s0:c18,c257,c512,c768 tcontext=u:object_r:userdebug_or_eng_prop:s0 tclass=file permissive=0 app=com.dexprotector.detector.envchecks
Or maybe it would also be possible to make them whitelist GrapheneOS since well... they're not Google?