@mjbrady
I personally use Microsoft account all the time since Windows 8.0, 8.1, and Windows 10 Pro, always set my secondary local account as Admin, and personally change my Microsoft Account login to Standard user, so no it doesn't run as Admin all the time, To Change account type, Open Control Panel, user accounts, Change account type, switch Local account to Admin, then Switch Microsoft Account login to Standard done
Avast works fine, all programs do as well
Sometimes get Popup from UAC for Admin account password, but otherwise don't mind that at all
Just thought i'd point that out regarding that