I think you've made reasonably good points. My least favorite aspect of discussing AI is the undercurrent that we're monkeys discussing the Sistine chapel. Ultimately, it's difficult to engage with the concept of superior intelligence.

Generally I think the outline that such a device would be a doomsday scenario for competitors remains quite plausible. This is somewhat easy to falsify because we would start seeing direct military action soon.

Taiwan especially is very vulnerable under this worldview and would be a pretty quick falsification.