WiFi calling is somehow conflicting with sprints network. I drop calls anytime I use it as well as get a location timeout message from the wifi calling app. I also cannot send mms via wifi, only data which worked on my note 8 and s9. Calls drop often whether on wifi calling or mobile network. Sprint believes this to be a device issue.
Recently I've fixed the mms issue via prl and profile update. Obviously cannot send mms over wifi to an iPhone. VoLTE is switched on but not active in my house because the wifi calling is active. I have switch to mobile data off. Router signal has no weak spots throughout my home.