I remember when Google broke 911 calling, and decided it was ok to wait for the next maintenance patch to fix it. People could have died, but Google just couldn't hurry up and release an emergency patch.
You can schedule a 911 test call. "Test calls can be scheduled by contacting your local 911 call center via its non-emergency phone number." [0] More info here:[1]
Phone makers (and even their supply chain partners) operate their own in-building cell networks with carrier-type hardware, and extensive debugging and observability, including simulation of multiple towers and location.
It wouldn’t get you 100% E2{ for 911 testing, but it does let you develop and test the stack extensively before taking it to the real world and scheduled testing coordinated with 911 call centers.
https://www.androidauthority.com/google-pixel-10-911-calling...