They know that Russia cannot win, it's too late. They had their chance and they blew it. Now is the time for the FSB to search for scapegoats on whom to put the failure on, in the typical KGB style.

These military know that, they know that if they come back to Moscow with such a defeat they will be shot by a firing squad. My guess is they believe that their best chance at survival is a putsch. There won't be a regroup and a new attack against Ukraine, a least not now, because they know that Kiev cannot fall with Europe supporting them. So these russian military will fight back, put the blame on the FSB and at the first opportunity the whole conflict will be over.

Russia will attack again though, in like ten years.