Create and export custom powerplans for desktop and laptop, add them to $OEM$ then import/set the required plan in setupcomplete.cmd.
Yeah I thought about that idea, and may still end up using it perhaps. Right now though I'm editing the power plan defaults, rather than the other methods since Microsoft now tries to constantly take control of your power plan and alter and reset your plans and settings back to defaults in Windows 10, so this is a more Microsoft-proof method for me.
The default keys method also allows the other stages of the Windows install process to use those settings as well which drastically cuts down on OS install time, like when you change the default power plan to be high performance, and/or customize the plan settings for speed instead of battery life.
But what I mean about testing is that every single thing I tweak I then go and test inside Windows as a user to see if it actually stuck and works. So like changing the default brightness for AC and DC power I will then reboot and go into my Windows power plans and reset things back to default and see if my brightness actually changes for real, that way I know I did the reg tweak properly.
Even if you change the attributes to unhide every single power plan option though, there's still about a dozen or two that won't show up for desktop users, you have to be using a mobile device of sorts and/or be on battery power which isn't possible for my desktop. So I have no way of verifying if those tweaks are valid with real world results. I wonder if there's a way to trick a desktop into thinking it's on battery power?