You aren't the only one.
I have the exact same issue on my ASUS ROG Zephyrus S GX701GVR, that my Panel OverDrive is now "gone". My Eventlog is full of failures from RefreshRateService and on every start of Windows, it fails to run the service "Panel OverDrive" service, which makes it so you can't use Panel OverDrive module in Armoury Crate.
I haven't had that issue before, and I don't know how to revert back from the newest update, since it's clearly bad.
I found a fix for mine. Which is, you have to uninstall RefreshRate from your Control Panel (if you have it installed there), and then install the RefreshRateService v2.1.0
Download link (from ASUS): https://dlcdnets.asus.com/pub/ASUS/GamingNB/AppforWin10/RefreshRateService/RefreshRateService_V2.1.0...