Hi, I understand your frustration. What Model doorbell do you have? Where you able to set up th Doorbell close to you main router/WiFi point at all? It’s best to do any initial setup in close proximity to your router as this will test the end to end solution is working. Then as you move away for the router then any connectivity issues are WiFi related (based on local conditions).
What do you use as your Router and WiFi solution? Adding extenders is not always productive as placement vs benefit requires some testing. The extender/booster can only work with what WiFi signal it gets. Speed is not King here, as the Ring units only need 2Mbps end to end connectivity, but it does have to be a quality connection.
Ring unit \<-\> home WiFi \<-\> home Router \<-\> ISP connection \<-\> Ring Cloud
Working out if it’s down to your WiFi is key, and checking your network neighbourhood is also a good idea to check if there is any local contention - a change of WiFi channel may solve such issues.
have you involved support since getting the replacement, as they can access a lot of data in the device that will maybe help them determine what the issue may be, apart from poor WiFi signal. The fact that a replacement also has the same issue, would suggest it’s something local.