Are you sure? They seem stopped. When was the last time they advanced? It seems like they have not been performing up to expectations for the entire war. They are fighting on their own border and they have not established air superiority or sea superiority. There are huge dysfunctions now evident in the Russian military tactics, equipment, personnel, etc. There was even a soldiers' mutiny. Why would we assume they are doing well? Maybe there are about to collapse? How do you know?