Video doorbell 2 no longer shows hardwired and no longer charges

I have a ring video doorbell 2. When I initially installed it, I hardwired it to the existing wiring. Everything worked fine for a couple years. Device reflected that it was hardwired. I never had to charge the battery and mechanical chime would chime when someone pressed the button. Then, one day, it just stopped being listed as hardwired. I suspected the transformer was blown, so I swapped that out with Ring's brand transformer 16v 30va. Transformer worked fine. Putting out 18v at the transformer and 18v at the doorbell. Then I thought it might be my mechanical chime. So I swapped that out for a chime noted on ring's website that is compatible. Still getting 18v at transformer and at the doorbell, but still not charging. Did the reset like every other article says to do. No go. If I cross the wires at the doorbell, the circuit completes and the mechanical chime rings. I'm at a loss. Am I missing anything? I'm told a diode or resistor is not needed for this doorbell as I have a mechanical chime on the circuit. Am I missing anything else? I have a feeling my video doorbell is bad.