Prevent Windows 10 from Locking When Monitor Turns Off

Windows Key->Settings->type "lock screen" in search bar, click "Screen saver settings". Uncheck "On resume, display logon screen".

If I want my computer locked, I'll lock it or put it to sleep.

Implies your computer is not asleep. However, sleep also has a lock option.

Windows Key->Settings->type "Sign" in the search bar, click "Sign-in options"->Change "Require sign-in" from "When PC wakes up from sleep" to "Never"

I have seen Windows update re-enable sign in requirements.

As Arana points out, in addition, there's a logon setting in the screen saver. Windows Key->Settings->type "Lock" in the search bar, click "Lock screen settings"->Screen Saver settings. This load the screensaver dialog. Ensure "On resume, display logon screen" is unchecked.

This is anecdotal at best, but, I used to have a dell laptop, and for quite a while I could not use the "turn off monitor after..." setting prior to sleep or the monitor would never work (remained black) unless I performed a hard reboot. While I had visited the dell site many times for updates, I finally tried going directly to the video card vendor (AMD if I recall correctly) and I found an update not on the Dell site for the integrated motherboard graphics and after installing, this feature started working again.

Major Windows upgrades can cause various problems, not all of them can be corrected by anything other than a full reinstallation. Below is my analysis of the problem.

I didn't find anything unusual in your report of powercfg -energy, so in my opinion your computer's settings and drivers seem not to show any visible problem. For this reason I wouldn't recommend updating the BIOS, as mentioned in the comments, as the benefits are unknown but there is always the risk of an unsuccessful BIOS update bricking the computer.

You say that you "use the blank screensaver for a couple minutes, and then just have the monitor turn off a couple minutes after that". As you don't want the computer to sleep or lock, I see no reason for having a screensaver at all. Turning it off might be a first step for isolating the problem.

Another long shot, but which sometimes helps to resolve sleep problems, is to Turn Off and Disable Hybrid Sleep in Windows. This is another step for isolating the problem, although the chances of it helping might be slim.

My last idea is based on your observation that "another user account on this same computer that functions the way I want it to". This might indicate profile corruption, probably caused by the Windows upgrade. This kind of problems are extremely hard to diagnose, and might not be worth the trouble.

The usual solution is to migrate to a new and uncorrupted user profile. Many articles have been written on the subject, for example Fix Windows Issues by Creating a New User Account. If the new account solves the problem, you won’t need to do a Reset, Restore, Refresh or reinstall of Windows.

Had this issue, fixed it by doing:

Click on Start and type: Lock Screen Settings. In Lock screen - click on 'Advanced slideshow settings'. In Advanced slideshow settings - there is a setting: 'When my PC is inactive, show lock screen instead of turning off the screen' that was set to ON, change it to OFF.