I do some watersports and always take my phone with me, so letting emergency services see my location is good for my safety in case I ever got into trouble on the water. I also have a PLB, but I like to have two devices for redundancy, as is best practice.
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.