you're making a category error, Evan.
People who aren't us don't give even the tiniest shits about which protocols they're using. 5G phones happily talk to 2G phones over SS7, and the only thing anyone knows about "5G" is that it's "fast" – and they don't even know what that means.
You just said approx. "that doesn't make any sense; it's like saying that you want NG-RAN and SS7 to be mutually intelligible" and people will care about as much as someone who literally says that.