Please elaborate what you mean by losing access. Don't you see registered fingerprints under Settings, Security and privacy, Screen lock and biometrics?
If the fingerprints are registered, have you checked if it is working properly in the Members app under Support, Phone diagnostics?
Make sure the Fingerprint unlock toggle is on in Settings, Lock screen and AOD, Screen lock and biometrics, Fingerprints. You can also turn on Fingerprint always on and set Show icon when screen is off to On Always On Display.
Also, when you lock your phone, do you choose the lockdown mode? That will require you to unlock the next time using a PIN.
