For the sake of an argument, let’s assume "The Outer Space Treaty (1967) has a loophole. If you launch from international waters (planned by SpaceX) and the equipment is not owned by a US-company or other legal entity there is significant legal ambiguity” is 100% true.

To use that loophole, the rockets launched by SpaceX would have to be “not owned by a US-company”. Do you think the US government would allow that to happen?