Peter, this should work with x440G2 or anything with 21.1+. It's necessary to have CC 3.0 latest in XMC (not 1.1 latest) to use further features of ZTP+ with XMC. Maybe this is your issue?
The upgrade process can be a bit long, and yes, I agree it's lacking at the moment status information: but this is coming.
Do you see the error message in the logs? Which one is it? What is your reference image?