"fits on a truck"

I think thats the problem though. Nearly all of the nightmarirsh drone footage attacks in Ukraine is dismounted soldiers. Seems like the best defense would be shotguns and some sort of electronic fire control if you wanted to get really fancy.

Layered defense. AND is better than XOR in this case.

The Ukrainian soldiers with shotguns can be overrun by an swarm and a shotgun’s effective distance isn’t great compared to how high drones fly for scouting. Better to have a truck mounted heavy weapon behind you and shotguns covering grunts on the front line working together.

That said, the front line of the RU/UA war is not the only useful place for this weapon. Presidential rallies, augmentation of the Iron Dome, defense of civilian airports, etc are all good candidates for a large truck-mounted weapon to counter swarms of drones.