WIFI Calling Preferences Being Forced to Cellular Preferred

Getting an E911 address set in the first place is the first essential part for Voice over LTE, video calling, and WiFi calling features to become active and usable at all in the first place, otherwise yours was functionally disabled without it, even though the toggle is there, with no E911 it causes IMS registration to fail, dis-allowing these functions entirely from the cell tower on device bootup. Testing with Airplane mode on then wifi, calls will drop regardless if E911 address is not in place, IMS Registration status is verified in SIM card status will tell you if Voice over LTE, video calling, and WiFi calling features are active and functioning Now that you have it, it WILL be a matter of time until you find this setting changing to cellular preferred constantly occurring throughout use as most ALL other carriers included Android 9+ Google software bundled phones go. Tracing through logs in App Ops I have identified this change over issue down to a combination of all softwares, implemented first by Google through most any Play Store apps eventually brought into standard Android OS development and also infused into vendor/carrier installed apps just the same is the ongoingly largest battery draining issue - randomly occurring wifi scanning also mixed in with Geo Location/NFC triggers which are all binded directly with GPS Location Services function. Bottom line primary trigger causing "Cellular Preferred" changes is limited consistent Wi-Fi internet data throughput or bandwidth, this by absolutely no means is wifi signal strength at the router but combination of all specifically between the modem itself and the wifi calling app itself on your device, home modem internet signals are rarely consistent although your wifi might be bad ass at hiding it for other types of devices; this can all drastically be affected also by excessive Google/games/apps limiting bandwidth to wifi calling app also multiplying the issue also having wifi scanning built into everything.