Cannot disable guest from lock screen

[AC Question]

According to Google I should be able to remove the Guest account from the lock screen in Settings > Users, then click the 3 dots for more settings. My Galaxy Tab S2, however, does not have these 3 dots for more settings. These tables are for my business and my requirements are very simple: one admin account and one restricted account. Most importantly nobody without those unlock PIN numbers should be able to use any of my devices. But from the lock screen anyone can just use Guest or even create a new profile. What am I missing?