I'm getting a prompt when trying to unlock my phone with my face that says something to the effect of "Face recognition unable to work while camera is in use".
Please try the resolutions provided by @Manikar and if you are still facing the issue, then could you please share the picture showing the error that you mentioned above?
If unlocking the screen with your face is not working properly, tap Remove face data to remove your registered face and re-add your face again.
I think I followed all of these tips properly. still getting the same prompt. would wiping my phone help fix? it does work half of the time; usually if I reactivate the lock screen a second time my face will register, but sometimes on the first try it doesn't.
As you are still having the issue, please backup the phone data using Samsung cloud or to the PC using smart switch software and perform factory reset.
