@JMAR
If you have a 1st gen Google Nest Hello Doorbell (and not the "Nest Doorbell [wired Gen2]" reported in your post), then your doorbell may be suffering from the same failure of the internal battery that has happened to hundreds of us.
Since the purpose of the internal battery is to provide power to the doorbell and its camera during the instant when power is diverted to ring the indoor doorbell chime when the doorbell button is pressed, when the internal battery fails the doorbell goes offline for a minute whenever the doorbell button is pressed.
This has now happened to all 3 of our 1st gen Google Nest Hello Doorbells. There is a workaround; turning off the "Indoor chime" option keeps the doorbell online because it no longer tries to ring the indoor doorbell chime. We have turned off the "Indoor chime" option and have instead turned on the "Visitor announcements" option (https://support.google.com/googlenest/answer/7672451) to get announcements on our Nest Hubs and Nest Mini.
See this very long locked thread with over 1,000 replies on the issue:
https://www.googlenestcommunity.com/t5/Cameras-and-Doorbells/Nest-Hello-Doorbell-cuts-out-when-butto...
Some customers have tried prying open the doorbell to replace the internal battery, with varying results:
https://www.ifixit.com/Guide/Nest+Hello+Battery+Replacement/131729
