On May 8, a Russian attempt to bridge the Seversky Donets river near Bilohorivka in Donetsk Oblast was defeated by Ukrainian forces, a single action in one day of fighting out of more than two months of war. But look at the scale of losses here.
Just from these drone photographs people have counted seven T-72 tanks, 31 BMP and MT-LB infantry fighting vehicles, five other armored vehicles, six trucks, and a work boat, plus the bridge itself. Note that if the turret is missing that means the ammunition in the vehicle exploded, killing the entire crew. Surely over a hundred men died here, perhaps many more than that, in this one small battle that probably lasted no more than a few hours. This is why most western experts say the Russian offensive is not sustainable and will run out of steam soon.
According to Ukrainian reports, most of this damage was done by artillery. Presumably it was guided by drones or forward spotters. Both sides can bring this kind of firepower down on any force that masses in the open.