If you haven't learned anything about the state of asymmetric warfare, an autonomous robot is going to be very expensive and timely to build and will be disabled by a $30 drone with C4 attached to it with sufficiently good skills at dodging. I'm assuming that we're in your supposed fantasy world where robotics has progressed to that point, meaning that the people opposing the robots also have access to much better drone software too, to keep things fair.

How do you do asymmetric warfare against autonomous self-replicating killer nanobots? In other words: AI-engineered bioweapons (with AI-engineered antidotes for the rich).