We're going to be adding a Location Scopes feature soon similar to our Contact Scopes and Storage Scopes to replace Mock Location. Mock Location works but requires a dedicated app and is global when people probably usually only want to do it for specific apps rather than breaking location detection for Organic Maps or whatever else they use for maps/navigation, etc.
Mock Location has an API to detect using it but there's no point hiding it since apps would ban GrapheneOS.