The FPS scanner got a major upgrade on the S21 phones and it is the exact same unit used on the S22 lineup. It is a Qualcomm 3D Sonic Sensor Gen 2. Qualcomm claims 77% more reading area, 1.7x more data captured, and a 50% speed increase. You can read more about it here:
https://www.qualcomm.com/news/onq/2021/01/11/introducing-qualcomm-3d-sonic-sensor-gen-2
Anyway, coming from a S21U and S22U, I have literally never had it fail, not even once that I can recall, in over a year using the same unit across two different phones. It is also instant fast - you can turn off the unlock animation and the moment you touch it, you're already unlocked. Also, if you have good "aim" with your thumb, you can simply place it on the black screen and the phone is unlocked and in your home screen before it even has a chance to "wake up".
Make sure you are re-training it after you install a screen protector, and if you have a particular finger that is giving you trouble, train it twice. Also, make sure when you're training it that your hands are clean and you're actually holding the phone in a way that you would when you unlock it. Some screen protectors will cause problems, and that is just the way it is - not a fault of the phone in that case. Tempered glass protectors in particular seem to cause problems with the FPS, but not all of them.
I don't use face recognition because to my knowledge it just uses a 2D image from the camera rather than a depth map (which means you can fool it with a photo). Also, I have to wear a mask a lot and face ID has been nothing but an inconvenience since 2020 - it is my #1 complaint about my iPhone, I hate typing in passwords literally 100-200 times a day for the most basic of tasks like unlocking a phone. Apple is way behind the times on the hardware side in pretty much every area except synthetic CPU benchmarks.