Russians have not even managed to shut down the internet in Ukraine yet. Nor have they established air superiority against a far less formidable opponent. Some soldiers do not even realize they are in Ukraine.
Totalitarian militaries always suffer from rigidity (a lack of seizing the initiative) and a lack of flexibility and adaptability, because dictators fear initiative and self-motivation -- anything that breeds independence.
When dictators fear being overthrown by the military, they take steps to reduce the risk of coups, and these steps have the unintended effect of reducing military effectiveness. Coup-proofing measures include promoting officers on the basis of political loyalty rather than merit, restricting training programs, creating centralized and convoluted command structures, and restricting self-motivation and initiative on the field of battle.