It sounds like you're in a region not supporting E911 but rather depending on Google's proprietary Emergency Location Service. We plan to make our own implementation of what that provides:

https://github.com/GrapheneOS/os-issue-tracker/issues/1174

GrapheneOS supports E911 and has our own network location implementation you can enable which gets used by it. Unlike Google's implementation, our network location is based on location position estimation similarly to iOS. Unlike iOS, we'll be providing full offline support for it.

Thank you very much for your work here!