Video Doorbell 4 no power

I setup 2 x Ring Video Doorbell 4 for a friend of mine and it’s worked fine for about 2 years. After charging the batteries until they go green, both of the Ring Doorbells will not power on. They do not show as active in the app. There are no lights on them after the battery is inserted. I even tried swapping the batteries and holding down the reset button. On a voltmeter, the batteries both read over 4 V (measured at the 2 outside contacts on the batteries). One of the Ring Video Doorbells is connected to a physical chime which chimes when pressing the button. Are these Ring Doorbells dead?