In WWII, F4 Wildcat pilots soon learned not to get into turning contests with Mitsubishi Zeros. Instead, they maintained altitude and speed, using their advantage in a dive to execute "slashing" attacks.

something that looks like a DJI phantom...the only way I seem them being useful is 1000 of them in a dense cloud around a target.. like stationary mines in the sky hoping to be struck by attackers like a bird strike.

Those drones are plenty fast enough for tanks. Why not a tank equivalent of an aircraft carrier? The tank would act as a mobile charging station and command center. Most modern tanks could be severely disabled by a shaped charge placed directly onto the barrel of the main gun, or directly onto the tread mechanism. The machine guns and targeting systems are also quite vulnerable, the loss of which would also severely degrade the tank's combat power. Tanks have acquired countermeasure systems like Trophy, but those could be overwhelmed through saturation attacks and on current tanks, they are externally mounted and themselves vulnerable.