Bioweapons are essentially a solved problem already, “AI” or not. In the mid 20th century the USSR had enough weapons manufacturing capability through Biopreparat to kill every human on the planet in less than 30 days. In the 1920s France had enough poison gasses to kill every inhabitant of Europe at the time. America and Russia each still have enough thermonuclear warheads to kill 95% of the earth’s population in under 30 minutes. None of these are new technologies, literally all of this technology is 50-75 years old and hasn’t developed much since because you can’t do any better than “total annihilation”.