I don’t know what is going on but with my 7 and 6 we’ve had zero issues with T-mobile Wi-Fi calling for over a year. The other week we both upgraded to XS phones and now have terrible Wi-Fi calling. I don’t know if it’s the phones, T-mobile or both. I have UniFi access points and it shows that the signal is perfect. Doesn’t matter if I’m 3 ft or 10ft from my router I am getting random calls failing. My internet is very stable (fiber). Really haven’t seen this before only after upgrading. Any thoughts?