Now that I know that Verizon blocks backup calling (among other things) for its own customers too, I figured someone must have other workarounds. I was expecting to find a Magisk module but maybe this is even better.
Disclaimer: I haven’t tried it myself but it claims to enable backup calling without root.
We’re talking about Verizon. The company that still refuses to unlock the bootloaders of the phones they sell.
My guess:
Band selection - 5g uses bandwidth more efficiently. They don’t want us using 4g anymore.
Backup calling - they want to sell you expensive roaming packages or hit you with insane roaming fees.