Faceid and passcode

As a guess, I’d say because Passcode Changes has been disabled in Settings/Screen Time.

UPDATE: I’ve tested this; if Passcode Changes are set to Not Allowed in Settings/Screen Time/Content & Privacy Restrictions then the Face ID & Passcode option disappears from Settings.

There is on mine, Settings > Face ID and Passcode, just under Siri & Search and above Emergency SOS.

You’re welcome. I like the easy questions 😁

Nice testing, should have finished my second cup of coffee prior to answering. But to add to your easy answers in the future managed devices can also cause this to disappear.