I am having the absolute exact same issue. I have factory reset it, removed and readded it to my Google home, but Nest refuses to recognize it. I am stuck on the same screen asking to select last 4 digits based on serial number. I posted a post about this same issue, no reply.
CAN A NEST SUPPORT MEMBER PLEASE OPINE ON THIS OBVIOUSLY RECURRING ISSUE? OR AT LEAST EXCHANGE THE CLEARLY DEFECTIVE PRODUCTS?
Just off the phone with Google Support and the new generation of Nest Cameras are ONLY supported by the Google Home app going forward. No current generation Nest cameras are supported by the Nest App.
Sadly Google is forcing the move away from a superior Nest App.
Thank you for your feedback on this issue, I fully understand the confusion of not having your new Nest Cams in the Nest App. I can imagine having to use two different apps at the moment is quite daunting, and could lead to frustration.
However, the new Nest cameras and doorbell are exclusive to the Home app because we wanted to create an integrated experience with your speakers and displays. A Nest Aware subscription applies to all of your cameras, speakers, and displays in the same home structure. Thank you for your continued patience, and support.
Please let me know if you have any other questions.
Thanks for explaining @GarrettDS but unfortunately the Google Home app is not nearly as simple or user-friendly as the Nest App so this is a big disappointment for many, i'm sure (including me). I design user web/mobile app experiences for a living and I cringe whenever I have to use the Google Home app... thank goodness all my endpoints (once added) can operate without it. At least for now they can...