It’s not just about limiting - why don’t these people make it easier on the apps themselves to do it? We know why.
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The Fix: Lock it Down:
Go to Settings > Screen Time.
Tap Turn On Screen Time (if not already on) and set it up for your child.
Tap Use Screen Time Passcode and create a passcode that the child doesn't know.
Go to Content & Privacy Restrictions (under Screen Time) and turn it on.
Tap Allowed Apps (to disable camera/other apps if needed) and Change Restrictions.
Under Content & Privacy Restrictions, find Date & Time Changes and set it to Don't Allow Changes or Require Password.