When I'm setting up my fingerprints I find it best practice to set them up as I naturally hold the phone and make sure some of my fingerprints are registered on all the four corners of the fps.
Also i set up 2 of the same fingerprint.
If a phone is still misbehaving after an update then I typically do the following.
1st option 》 Turn the phone off and then from a set series of button presses go into the phones system files and clear the cache.
2nd Ootion 》Back up and then remove any relevant Sd card and factory reset as a last resort.
3rd Option 》 Let a Samsung Experience Store or Samsung Service Centre have hands on.
I wish you all the best with this situation.
My advice comes from being a UK Samsung Phone Owner.
I have no affiliation with Samsung.
Current Phone ~
Samsung Note 10 Plus 5G _256Gb >_ Samsung One Ui 2.5/ Android 10.