Technology

Between GPS (jammable but likely gets you into the target area), dead reckoning, optical flow sensors and increasingly impressive onboard camera processing, RF jamming will soon be irrelevant.

Almost a decade ago I was flying agricultural mapping missions that were 99% autonomous, and the parts that weren't were problems a military drone doesn't have (soft launch and landing)

The clear counter is autocannons, likely fully automated themselves to manage large swarms. The other would be cheap anti-drone missiles that either are basically a drone themselves or a glorified model rocket. Possibly tiny, cheap and fast interceptors launched from fixed-wing drones. The weak point of drones is literally their physical weakness.