I have the same found and have found the face recognition often hit and miss. I've even entered an alternate face (of me naturally), so it has two different views to choose from. I personally had better luck, in the past, with eye recognition on an older note.
@yayo151 are you concerned with security, or ease of use? I've rarely had issues with face recognition (except when in dark areas, when wearing a mask, etc.), and it is extremely fast. But it's also insecure, and can be tricked by a hi res photo. So you can't use it for certain Samsung Knox secured applications like Samsung Pay. Long story short, if you're not worried much about personal security then go for it. If you are, then stick to the fingerprint scanner.
Disappointed with face recognition on mine. Oddly better on S20. Used same method, two face profiles. I miss how well and easy iPhone works consistently and quick from iPhone X thru 11 and 12. So I usually end up using fingerprint
Having come from the Note 9, I won't use the facial recognition feature. I wish that they had kept the far more secure iris scanner, but Samsung has to make the screen more important than any useful feature.
If it is not reliable enough to be used for Samsung pay, then I will just have to put up with fingerprint only unlock.
It works 75% of the time for me. Same for the finger print sensor under the screen. I miss the finger print sensor on the back of the note 9. Besides that the phone is fantastic.