Baghdad Bob was more credible.
The casualty counts derive largely from artillery and guided bombs.
Big death numbers do not come from drones because they don’t have payload capacity for substantial explosions.
Artillery shells and bombs.
In the case of artillery, there are casualty generation models available for all forces around the world. A good estimate for deaths per shell for various presumed accuracies can be computed — provided you know your own weaponry well.
Russia does. Ukraine doesn’t. The stuff arrives, they get trained, there is no accurate modeling.
So Russia has a pretty good picture of Ukraine losses. The reverse is not true.