Exactly. There is no way to make that work without ending up with a pile of absurd results, or results that are "right" but for legally contorted reasons.

The answer (to this narrow question[1]) is to not do business with shops like 23andme, who are horrible gossips. Find a service that actually respects you and your wishes if you want a test.

Admittedly this will become harder as testing becomes part of medical care. But telling your doctor not to tell the insurance company what's going on would never fly anyway.

[1] To the broader questions of medical privacy, well, burning the private insurance industry to the ground and chumming the PBMs would be a good start.