Hi Sheena,
Welcome to the forum.
Windows 10 should be remembering your settings, but I am a little confused by your post. The settings you are making are they for when your Acer Projector is attached and turned on?
If that is the case you may find when you reboot if this projector is not on, or connected then Windows is defaulting back to PC settings. When you turn your laptop on next, press the Windows key + P key which will open up the Project panel where there are various types of setting options - one of which may be storing your specific choice.
Alternatively, you could consider right-clicking on Start then left-clicking on Device Manager and when this opens locating your Display driver, and uninstalling then reinstalling it, or checking if there is an update for that driver which may be better suited for Windows 10.
If you want to uninstall the driver you right-click on your Display in device manager and select uninstall. Just note if you do this it will remove the driver from your computer so you will need to use the disk that came with computer, or download the driver again to reinstall it.
With the driver uninstalled Windows will default to a generic display driver until you install the one intended for your laptop.
Regards,
Regedit32