You don’t need to load the compute onto the platform for autonomy, planning can be done remotely just like with human guidance. The latency is the same.
I would note that a lot of drones are quite large too - small airplanes. They can carry more than enough hardware for autonomy. You can also have motherships doing planning and smaller kamikaze drones for combat.
These aren’t hard problems to solve, the harder problem is the reluctance to give over to automation. But that’s going to happen faster and faster.
Long spooling optical fibers.
We will have a fully autonomous Siri that is actually good before Ukraine gets autonomous motherships making targeting choices to repel Russian assault corps. However, given the pace of the war and the pace of AI development, that may actually happen. But it isn't happening today.