Re: Not that simple - some 4G/5G devices and/or SIMs currently use 3G and 2G for voice!
That is called 5GVoice (Vo5G/VoNR) and that standard is not yet ready for use. That means all 5G networks are going to be data only for a while. Currently there is also no support for 5GVoice in any mobile phones on the market that I know of (it might be built in but not enabled).
VoLTE and Vo5G are both build on IPv6 network connections.
Source
https://www.nokia.com/networks/solutions/voice-over-5g-vo5g-core/
https://www.ericsson.com/en/5g-voice
Biting the hand that feeds IT
