I have been working for months to try to get my phone stable to make calls and send text from my home. Works great on 5G, but signal quality at my home is terrible on this phone where my Wife's S10 has no issues at all.
I should be able to do Wi Fi Calling according to my carrier but it would turn off constantly. I searched for an answer with my Cell Carrier and through online Chat and spent hours with no solution. Today I stumbled on this, which at least puts a band aid on the issue: https://us.community.samsung.com/t5/Galaxy-S21/Workaround-for-WiFi-Calling-Keeps-Turning-Off/td-p/17...
My question is what is Samsung doing to address a problem with one of their most expensive phones?
For me I use a network switcher app. I use WCDMA network which is 3G only which utilizes your Wi-Fi for both calling and data use. When using Wi-Fi Calling i make sure my data network type is IWLAN. So that I know I'm totally using Wi-Fi for Data and calling.
Also very important make sure your Emergency Location Information is up to date