@Handrahan
If you are getting a message indicating your doorbell is still connected to another account, it's possible that your factory reset was not successful.
If you have a 1st gen Google Nest Hello Doorbell (since you marked the Nest app in your post), you need to do the following without disconnecting your doorbell from the doorbell wires:
Hold down two buttons on your doorbell for about 10 seconds.
Hold down the reset pin on the back (insert the release tool or paperclip into the hole near the top).
At the same time, hold down the big doorbell button on the front.
Your doorbell will chime and its light ring will start spinning blue, then flash yellow, and then all the lights will turn off. Release the two buttons.
The factory reset is complete when your camera chimes and the light ring starts slowly pulsing blue.
If you have a 2nd gen Google Nest Doorbell (wired) (as indicated in your post, you need to do the following:
Insert and hold the reset pin (you can use an unfolded paperclip or a thumbtack).
At 10 seconds, the status light will blink yellow four times, and you'll hear a countdown tone.
At 12 seconds, the status light will be steady, solid yellow while the doorbell starts the factory reset, and you'll hear a confirmation tone.
Release the button. Your doorbell will restore to its factory settings.
See the Factory reset instructions here; they are after the "Restart" instructions:
https://support.google.com/googlenest/answer/9252162
