Windows 10 sets power plan back to "balanced" every time I reboot
Good thing you have the Pro version. Go to the start menu/search bar and type gpedit.msc
I'm not sure EXACTLY where it's configured, but in group policy (local policy, assuming you're not connected to a domain), find the power option configuration and set it to whatever you want. The policy will take precedence over any other settings.
Once set, open up command prompt as admin, type "gpupdate /force" and then let it do its thing and restart your computer afterwards. Now your computer has a policy letting it know exactly what settings it should be for your power plan.
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Local Computer Policies > Computer Configuration > Administrative Templates > System > Power Management
From there you can change settings as you see fit. You can't do this with W10 Home, but Pro you can. @Fraser Cow