800? No way unless they are counting getting muddy as a wound.
The numbers released from something like this are always suspect and only become accurate long after the fact. However, the Russians are being slowed significantly which means they are taking casualties and losing material. The Pentagon is saying that Ukrainian air defense is degraded by still functioning and that they still have active aircraft. If that is true it means they Russians are taking a pretty bloody nose and failing to reach objectives. Will be interesting to find out what they losses actually are.