Drones are changing warfare, but they are not the super weapon that they sometimes seem to be. They work best in combination with a variety of weapons. It usually takes many drones to take out a tank.
In many situations, mortars are more effective than FPV drones.
FPV drones can’t fly far, can’t see well at night, don’t work well when it’s cloudy, are vulnerable to jamming, and have light payloads. Mortars are better in these respects. You can make a drone that doesn’t have these disadvantages, but at that point, you have an attritable weapon that is much more expensive than a mortar shell.