The May security update for Galaxy A30 added an abilityto take the slowmo videos, but there was no option to switch to the Slow-motion mode. However, you may actually make it available with reseting the camera settings. It won't delete any of your pictures in gallery, but you may lose the changes you might have made in the camere app.
in India they get June update with slow motion and july security patch but in my UAE region phone update are not available even I did not get any slw motion
Face Unlock is not 100% secure in most devices, in addition, Samsung always warns you about that before you unable the Face Unlock feature. That's why I don't prefer this feature to unlock my phone, but you may use intelligent scan IRISIS for more security.
