Hardwired Video Doorbell 3 No Longer Charging Battery or Showing Hardwire Connection

I installed a Ring Doorbell 3 almost two years ago using the wiring for my existing doorbell. I have it ringing a Chime Pro but I did hear the chime box make a very faint electrical buzzing noise when pressing the doorbell before I set up the Chime.

Long story short, I went nearly a year before I was told I needed to charge the battery. After that, however, I have had to charge the battery every couple of months. I checked the Device Settings today and it shows it is running on battery and not the hardwired connection. The wifi connection is good, so that isn’t the problem. Nothing has been done to the doorbell wiring since installing, though I did install a new door and kept the existing wiring.

Any thoughts on what the issue could be?