Finally figured out a solution (workaround?) for getting iCUE to detect my ASUS Z370 motherboard. Run iCUE as Administrator.
I noticed when launching iCUE, in Event Viewer, I would always get this error when the Plugin kicked in:
Unable to start a DCOM Server: ..... The error:
"2147943140"
Happened while starting this command:
C:\Program Files\ASUS\AacMB\Aac3572MbHal_x64.exe -Embedding
Finally decided to try Googling the error code: 2147943140 = 0x800702E4 = ERROR_ELEVATION_REQUIRED
Launching iCUE as Administrator stopped that error and now iCUE detects my board like it used to...