I’m not OP but I just want to point out that navigation doesn’t need to mean I am always sharing telemetry with multiple third parties

I have a garmin watch which is great for overland hiking, multiple day expeditions etc

I download the maps and the watch has GPS to plot where I am on that map. My watch doesn’t have an eSIM at all.

Rivian is an adventure brand so if they wanted to design a maps system like that, where I am not continually downloading tiles from open maps or google and sending my location to them and others, they probably could

I just don’t think they have space for those types of features most people don’t care about while they are trying to compete in a rough industry and deliver new vehicles

Why would you be sharing that? There's no reason why the navigation system needs to constantly tell a remote system where you are. Navigation systems don't even need an Internet connection for basic routing.