wi-fi calling

Any suggestions on how to measure and improve wi-fi calling. Kit is iPhone 11, EE carrier, ASUs rt-ax88u, virgin supplier broadband. Ping is 170mbs over Wi-Fi. Phone calls drops out when in same room as router and on Wi-Fi calling. Been issue for months. Hoped my new router would resolve...

Hello, I have an ASUS RT-AC3100 router on ASUSwrt Merlin 384.4_2, and something seems to be preventing my iPhone from using Wi-Fi Calling. When on any other network, it works fine, but on my network, the "Wi-Fi Calling" carrier signal shows up only for a second, as if the VPN tunnel is...