The reason some are obsessed with atc frequency boundaries on charts is so we can go back to a form of “radio arranged separation” that existed between IFR and VFR in most un controlled en route airspace. That was when IFR and VFR used the quadrantial rule and flew at identical levels when on the same heading .
Under ICAO class G does not require radio for VFR. It is considered a see and avoid airspace.
If safety dictates that traffic information on VFR is required for IFR aircraft then that requires a minimum of class D.
Some try and turn G into D re VFR traffic. Unfortunately will not work.