ProfessorMonks 5G means 5G or below, which allows using all the supported protocols. It provides maximum compatibility and overall connectivity/performance. It's the default mode in AOSP and why it says it's recommended so people know which one to go back to if they have issues. We do not plan to change that.

Using our added settings ("4G only", "4G or 5G only" or "5G only") requires having VoLTE/VoNR for working calls, will lose connectivity if only 3G is available, etc. It is not the default for a reason, and we aren't giving a general recommendation that most people use the attack surface reduction feature. It is there for people who can accept the downsides for reduced attack surface. It may improve battery life but it can also reduce it, that depends a lot on the available connectivity.

AOSP recommends the default setting good reason. Many people already have issues with setting "4G only" and not understanding that lack of their carrier fully supporting it is why they don't have working calls anymore, etc. We don't want to make changes which would make this worse. The settings are for people who understand the consequences.

      GrapheneOS Using our added settings ("4G only", "4G or 5G only" or "5G only") requires having VoLTE/VoNR for working calls

      Can someone who has data-only SIM safely disable VoLTE and still use their phone for cellular Internet access?
      Will things like checking balance with short code in Phone app work in such configuration?
      Is it something GrapheneOS would recommend doing for attack reduction purposes?

          GrapheneOS Many people already have issues with setting "4G only" and not understanding that lack of their carrier fully supporting it is why they don't have working calls anymore, etc.

          Just to add, as far as im aware the carrier will support this but need to be contacted for it to be enabled.

              tango They don't usually need to be contacted to enable it. Some require that if you use a non-carrier phone.

                thmf You shouldn't need VoLTE/VoNR enabled if you don't need carrier-based calls. You may still need SMS but there isn't currently a toggle for SMS as a whole.