I've requested for something to be done about this during the beta on the Note 20 Ultra along with 44 others and still to this day I have not received any word nor response to this suggestion.
I have to use two fingerprints from each thumb just to get a good read on the fingerprint sensor to unlock my phone. This is due to me having a screen protector. Because of the limitations of the fingerprint sensor, my prints are not always read when trying to unlock. The current number of fingerprints we can save is 4. I have to save 2 for each thumb just to get the phone to unlock somewhat normally.
So here I am again, maybe with more people behind me this time, suggesting and requesting for you to add the ability for us to save more Fingerprints! 4 fingerprints is not enough Samsung.
Regardless of what you may believe, having two of the same fingerprints does make the phone unlock faster. In fact, in the tests that I have done, the phone recognized my fingerprint faster and seemed to me more accurate with two same prints, even faster with triple and almost instantly with all four prints as one finger. I would like to add my index fingers, but I can't do that unless you enable the feature of more Fingerprints...
Screen protectors suck but they're a necessity to some. Especially when I paid nearly $1500 for a phone, I'm going to use a screen protector protector for my phone.
A simple request to make things easier for us users isn't to much to ask right, or is it?
I would suggest using the feedback section of the app and send it that way. This is a support section, so I don't think it does any good to post a suggestion here. I'm sure there's also a balance between the number of fingerprints and speed. If you have 50 fingerprints setup, the system has to scan through all 50 to find a match and could be slower. Maybe 4 is the best balance between this. Who knows.
Samsung never responds in the feedback section. All they send back is the same generic response every time. It usually states that if I'm having problems with connection to data please follow these step:... Or some other off topic response. This is the only place that someone from Samsung responds or that I can get a response. Also to answer your other point, I believe you are correct but we don't need 50 Fingerprints. Maybe just 6 or 8 at the most. Which is more than enough I believe.