Most smart doorbells (e.g. Google Nest Hello doorbell) seem to require a wired connection. The Ring wireless doorbell looks like the most popular but compatibility with Google Assistant looks poor. I can't tell if Ring would chime on Google Nest but it looks like I can only ask Assistant to tell me things rather than it proactively do them...
I want a wireless (i.e. battery powered and wifi) doorbell that chimes on my Google Nest speaker and I can also access video (separately, not on Google).