WIFI Calling Preferences Being Forced to Cellular Preferred

Solved! ! ! Not certain how may people are still having this issue since Android Pie update but I think I have found my solid working fix for WiFi calling continually flipping to cellular preferred, I am on TMO Samsung S8 Active but from the sounds of things this should do the trick for many other carriers or devices if any others could please followup with further testing. After trying numerous other discussed attempts and further digging I found out all I needed was a simple tool I already had from battery saving mods, no ROOT is needed at all but can be accomplished just the same if you are. First step coming closer to making this work, I turned off WiFi scanning by searching for it in the general settings menu of android, this is to help avoid any extra unneeded wifi signal interuptions, not certain how well thia plays with any "companion device" users but may, I have no purpose for these. I use Greenify and Island to debloat/disable unneeded apps from my user interface that application manager fails in ability to do, a computer with ADB installed and options enabled for such in Developer Options, search XDA for setting these up, most of this was just for battery savings essentially and is unneeded but good help. The app I installed which I found fixes our issue is App Ops - Permission Manager from play store, using a computer loaded with ADB and dos/command prompt terminal to send commands to grant needed permisions. Once in App Ops, make sure system app options are checked and scroll down almost all the way to the bottom to find your systems WiFi calling app and set "coarse location" option to "ignore" to prevent network scans from triggering this hated event and then also set the "modify system settings" option also to ignore blocking changes from occurring. I also have coarse location on my Phone app set the same too but I don't think it matters on that app, I had set the phone app previously as such with no effect until tweaking the permissions on the WiFi Calling app itself. Using App Ops I find you must reboot also for permissions to take effect. I have multiple wifi routers setup and hotspots from work I used to try to force a change-over to happen as WIFIs change or diminish out of range(as this function is implied with its label), my WiFi Preferred calling method is now finally under control. If you choose to use App Ops to resolve this issue or expirement with the others, only use the suggested options for the WiFi Calling app, all other options I tried on it either crashed the app or breaks IMS Registration otherwise which is needed for Video/VoLTE/WIFI Calling features. Tweak/debloat any other apps you wish to save battery/data at your own risk one by one, especially any other features in App Ops, very easy to break functionality of any of these or other functions if you tweak too much all at once like I did to try to fish through what messed up something else(good thing theres a select all/restore to defaults option) tweak little by little if you do, I was one of those standing at the store and on tech support for endless hours set on it being my out dated sim card then 2 new sim cards doing the same before finding out I tweaked to many settings same day I had got my new sim card