Yes, but if you violate the laws of war in an attack (e.g. if we stipulate that Ukraine did use a truck bomb, either with or without the knowledge of the truck

Yes, but if you violate the laws of war in an attack (e.g. if we stipulate that Ukraine did use a truck bomb, either with or without the knowledge of the truck driver), then the entire attack is unjustified and the collateral damage becomes murder.