Stuck in the mud, forests, without food, fuel, and comms. Russia is already mobilising its reserves from all the way back as Vladivostok (7000km away,) which means they had a very, very, very serious, life-threatening reason to do so.
We can also conclude that Russia didn't commit its fancy new weapons to the assault, making the claim that most of them exist only on paper, and to appear on parades so more stronger.
The state or Russian military hasn't changed at large since the Second Chechnya War, except now they lack military veterans from Soviet era.
Russia is blessed by only having NATO as its only adversary, and this gives them ability to concentrate on Ukraine.
If we had a hostile to Russia regime at least in Belarus, Georgia, or Kazakhstan, they would've gone for landgrab in Russia WITHOUT HESITATION now given just how weak is the Russian conventional military. People die, and go, cities fall, and are built again, but borders stay for centuries. This would've been a once in a century opportunity for them.
Kazakhstan can return to being a nuclear state overnight if they capture Orenburg. 50% of Russian nuclear potential is a taxi ride away from Kazakhstan border.