Ret@uvok that depends on a lot of things. In this day and age with VoLTE and Wi-Fi Calling it shouldn’t be. In lots of (most?) places 5G isn’t proper standalone 5G and actually uses the LTE packet core anyway (5G-NSA) so “5G Only” is a tough ask.
Maybe your phone couldn’t find a suitable cell to register on given the restriction of 5G only and that’s why you couldn’t make any calls?
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