I rarely post to forums, but my experience with my Nest Hello and Google Nest Support is worth sharing.
Purchased new Nest Hello on July 6, 2023 to replace one with cosmetic damage (purchased before the Google takeover). The Hello worked fine for 5 months before going offline. Following advice from this forum and Google websites, I made multiple unsuccessful attempts to re-add the device. Two weeks ago, I placed my first of 6 calls to Google Nest support. In the first call (1.5 hr) support walked me through a number of possible fixes (create new home, remover power, use mobile hotspot, etc). All failed. They escalated, and told me expect an e-mail reply in 2 days. The e-mail never came.
Every subsequent call was a start from scratch effort, repeating the same fixes and dealing with a support tech who could barely understand english and often provided wrong information (the Hello can only be added to Google home, etc). I re-installed by old Hello and it connected to my Nest account on the first attempt.
After 2 weeks of this, and a non-functioning Hello hanging loose at my front door, I filed a warranty replacement request. The first request was lost in the crack Google/Nest support system, and I just got off the phone for 1.5 hrs working on a second request, with an equally incompetent support rep.
Bottom line: Google would not honor the warranty because I purchased the Hello from Amazon, a third party. This, despite the fact it was purchased from the Google LLC storefront on Amazon. Google/Nest support told me the same would hold true if I purchased from Home Depot.
Good companies stand behind their products. Not doing so is a poor business practice, and one more reason I stay away from the Google ecosystem. But throughout my experience the Google/Nest support was the worst I have experienced. And I've experienced cable company support.
