Ring Video Doorbell Plus connection nightmare.

Four weeks ago, our Ring Doorbell Plus randomly went offline. At the time all other Amazon Alexa, Roku, and Apple smart or streaming WiFi devices in the home were connected and working without interruption. Prior to this event the Ring Doorbell had been working without issue for four years. The next day I followed all the reconnect steps in the iPhone Ring app. I tried a one quick press of the reset button on the side of the Ring device. The Ring would give me a verbal announce, "Ring is in setup mode" and show me a spinning white light. When I got to the portion in the set-up of choosing WiFi it gave me a random Ring WiFi address ( Ring-bc0cb37 ) but then tell me "Unable to connect". When I followed the manual connect instructions and go to the Ring network in Settings on my iPhone I could see my router as well as most of my neighbor's routers but no "Ring" listing. I checked connections. I tried powering off and restarting the router. I tried restarting the modem and the router. I tried removing computer eithernet cables from the router and turning off all streaming devices that use the router. I checked to make sure I had the most current version of the iPhone Ring app, and I also tried deleting the Ring app from my IPhone and reloading it. I tried reconnecting using a different iPhone. I tried powering off the Ring doorbell at the breaker panel. After reading through Ring customer forums, I saw a number of people having router issues with the Ring doorbell being too far from the Router. In a small house I did not think that was my issue but I purchased a new Router. Then I purchased a Router extender and positioned it 4 foot from the Ring Doorbell making sure that the WiFi network was set to 2.4 ghz.  After installing the new Netgear Router and Netgear Router Extender all other Apple, Amazon Alexa, and Roku streaming and smart devices continued to work seamlessly and without issue.   Only the Ring Doorbell would not connect. September 28, I had my first phone appointment with Ring tech support. After walking through all the troubleshooting instructions with the tech-support agent I was told I would need to purchase a new Ring Video Plus Doorbell. I ordered a new Ring Doorbell Plus which arrived a few days later. I followed all installation instructions and installed the new Ring Doorbell. It connected immediately and worked without issue. Six hours later it disconnected and would not reconnect. As before all other Wi-Fi devices in the home continued working perfectly with no interruption. The next day I followed all of the reconnect instructions again but to no avail. I set up a second phone session with Ring consumer support. The second Ring tech walked me through many of the same troubleshooting procedures again. At the end of the call the second tech advised me that I needed to replace the transformer on my mechanical doorbell chime with a ring transformer and sent me an image of the Ring transformer I would need to purchase. The next day I ordered the Ring transformer the tech specified. When the new Ring transformer arrived, I had it installed by a licensed electrician. I also had the electrician inspect all the wiring and connections, as well as testing the voltage at the transformer, mechanical doorbell chime, and at the ring doorbell itself. The electrician reported no voltage problem, and all tests measured 17.6V. I tried following all the reconnect instructions in the Ring app, and again the Ring doorbell would not connect. I set up a third phone session with Ring Consumer Support. After walking through all of the troubleshooting exercises with the third tech, he advised me that the second Ring Doorbell Plus that I had just purchased was defective and would need to be replaced.  I returned the second Ring Plus Video doorbell.  September 11 I installed the third Ring Plus Video Doorbell.  Installation again went smoothly and connected to WiFi network immediately and without issue. The third Doorbell worked perfectly for six days... then randomly disconnected yesterday morning. As before, no other WiFi, Streaming or Smart device in the house were having any issues. Amazon Alexa Echo, Roku Television, Amazon Smart Plugs all working normally without interruption. Yesterday I spent another hour or so one the phone with Tech Support and once again went through every conceivable trouble shooting procedure to get the Ring Doorbell to reconnect but without success. I've replaced the Ring Doorbell plus twice. I Purchased a new Ring Transformer. I had a licensed Electrician do the installation and inspect all wiring, connections, as well as test voltage output at transformer, mechanical doorbell and Ring Plus unit. I replaced the router. I purchased a router extender. I am currently still without a doorbell and in process of trying to return the third Ring Plus. 4 weeks and countless hours trying to get this doorbell to work without success.  Two things are very curious about all this. The first is that through all of this other than powering off and replacing the Router, not one interruption in all the other Amazon Apple and Roku WiFi devices in the house. Also, all other devices reconnected seamlessly with the new router. The second is that all three Ring devices exhibit the same behavior. They would initially find the WiFi network and connect immediately without issue but only the very FIRST time they were put into operation. After connection they would operate normally for a period that varied from years to hours, and then each would randomly disconnect. Once they disconnected, even with Tech support guiding me through all reconnect steps, none of them will reconnect after the first time they disconnected.