I recently set up my doorbell, and noticed the chime is linked separately afterward as an Extended Device (like how the Spotlight is an extended device of the V3).
What happens if you DELETE the chime from the doorbell (not just unplug the chime, since the phone will keep searching for it)? Then the doorbell might stop broadcasting in that frequency range and thus there would be no interference anymore because it’s no longer trying to stay connected to a chime. Then you should also unplug the chime after deleting it (to ensure it doesn’t cause any problems either).
Then the doorbell will still work with your phone(s) and you can presumably have Alexa Echo devices sound a custom chime/audio/alert when someone presses the doorbell button.
The VDB would presumably have no reason to broadcast on that frequency if the chime is deleted from the device, but should still otherwise function normally. Maybe test it out? It’s not the ideal resolution, but it would be an informative test, and it would allow use of the VDB…and there alternatives (Alexa) for getting the chime noise that wouldn’t cause interference.
In addition to Alexa, there is a way to force Google Assistant devices to broadcast a custom sound through Webhooks or Tasker, but it is a little more complex than the user friendly Alexa option.