Forum Discussion
Stop Microsoft's nagware pop ups
Once more, I'm on a new computer which has reset all of Microsoft's nagware pop ups that remind me how to use a product I've used for literal decades. "Did you know you can click here and do this". "...
This discussion might be what you're looking for:
Disable Office Teaching Callouts - Microsoft Q&A
I'd only try the registration solution proposed at your own risk. It might be safer to simply dismiss the Callout when it appears and move on.