Too bad that all govt drones (not COT toys) operate above audible and visual range from the ground. Much less shotgun or even rifle range.
Just as the best platform to take out an airplane is another airplane, and the best platform to take out a tank is another tank, anti-drone drones are going to be the ticket. I’m sure there plenty of them under development in various military R&D labs.
For now. They are scaling down to drones of much smaller sizes and utility.