Updated 09-25-18: Smart Eye Protection option has disappeared (again).I factory reset my phone since first starting it, as I still have issues with the alarm in Google's Clock app not sounding

After the reset, the Smart Eye Protection disappeared from this phone, too

And it looks like the Smart Eye Protection feature has been restored, so that's a win

Issue #2 resolved: The Smart Eye Protection feature has been restored

When I first opened and started the phone, I saw the Smart Eye Protection option in the Display settings; however, after factory resetting the phone several times (to see if the alarm would start working), the Smart Eye Protection option is no longer listed anywhere