Apparently this was not how you remove the doorbell from its mount. What is the function of the ripped off ribbon cable? The doorbell is still showing signs of life.
I can't make out the cable info in the pic, but you might be able to find it on Ali Express or something. It looks like just a few screws to replace it.
Of course Google wants you to just buy a new one though.
A few chats with Alphabet customer support informed me that it's not user-replaceable without a pretty big risk of further damage, even if you want to go through the process of a full teardown.