I am wondering why they used the link so much that it was able to be used against them. Submersible loses benefits if it requires an external service.

Launch. Submerge. Drunkenly move in the direction of the destination. If N days since last check-in and/or uncertainty in location, ping mothership. Repeat. Only lean on communication channel for final handoff stage.

To that end I suspect that tracking starlink used in an unmanned narco sub would be trivial for an insider at the company. My first thought was “I wonder if the movement and activity pattern would be unique. Yes probably. If unique could a script be run to pinpoint them? Yes probably.” If law enforcement has tasked someone with doing this (likely and legal) there’s high likelihood that any future narcosub using starlink will be intercepted. So to anyone on either side of this arms race: “you’re welcome”