Where does the AI get the sufficiently large drone army?
The self driving vehicles could target food delivery -- not your ubereats, but farm trucks and roads. Destruction of logistic infrastructure results in mass starvation. Individual targets for a complete eradication would take more effort, but a significant cull of the global population seems quite feasible with today's tech.
But folks are also doing virus research with AI. If such a lab gets hacked to make a super-virus, and its containment gets breached by a kinetic impactor, it could be cataclysmic.
But I hope you're right! It's not like the world's armies have enough nukes to eradicate all data centers or anything.