The initial Spanish conquest of the Inca empire by 168! Spaniards was not a question of disease as much a war of succession the Incas fought amongst themselves that Pizarro knew to exploit. Throw in horses, steel, and gunpowder and you have a one-sided affair.

This is not true of everywhere that was colonized. See Africa, or India. It would not be possible, even with very great tech advantage, to sustain millitary campaigns so far from europe without a safe port to base supplies etc, not to mention the manpower etc. These were very much made possible by what was essentially a standard playbook of allying with some natives against others, and using trade imbalance, violence, strongarming and other things to turn those "allies" into protectorates, and eventually colonies

Wait, you think AI won’t eventually have full control over a bio lab, where it can manipulate an unsuspecting tech to produce and release a bioweapon to accomplish that explicit goal?

Because I think that seems virtually inevitable at this point.