I have an interesting situation with my Galaxy S21+ 5G phone.
The fingerprint sensor works very well for unlocking apps. I barely have to tap my thumb on the sensor, and apps quickly sign me in.
The same is not true for the phone itself, where the fingerprint sensor only occasionally unlocks my phone, and I usually have to use my password instead.
Why does the fingerprint sensor work so well for signing me into my apps but so poorly for signing me into my phone?
Attention Samsung Moderators: I have already tried all the steps listed here https://www.samsung.com/us/support/troubleshooting/TSG01200322 including the other steps after the "No, I need more help" option on the page, including the video "How to setup fingerprint security on Galaxy phones." I ask you kindly not to suggest these steps again and then mark my question 'solved.' In particular, please do not presume I have a screen protector - I do not have a screen protector. Many thanks.
If you've already tried re-setting up your finger print (although, i doubt that's the issue since you say it works well for apps) you can try submitting the issue to Samsung Members app if you haven't tried yet. They might be able to help.