It's very clear that the Russians badly screwed up their logistics chain - see https://www.youtube.com/watch?v=b4wRdoWpw0w for a good obvious breakdown. But they also dramatically underestimated the morale of Ukrainians and also badly miscalculated NATO's response. NATO is flooding UKR now with drones, anti-tank misles and surface to air missles.
They also have failed to have clear armor and air supremacy. They have fed some of their most "elite" VDV units into a meat grinder by sending them directly into Kyiv without any support, under the thesis that the Ukrainians would leave them uncontested, or where not able to maintain a reasonable response.
Nevermind that Ukraine is mobilizing quickly (pre-war calculations where 30 days to build a effective force), while 75% of Russia's strike forces are in theater, and 95% are committed to battle.
Because of all this - Russia is in a no-win scenario. To hit their goals will result in sanctions staying in place - and eventually destroying the Russian economy or alternatively leaving them as a vassal state of China. If they retreat, they may save their army, avoid a vietnam scenario, but Putin will loose face, and Demcoratic forces will be revitalized inside of Russia.
Or they just stay where they are at. Inching ever close to Kyiv, but never winning any strategic victory.
Forces are pushing towards stasis right now.
I'd never bet on it - it's disrespectful to the dead and those fighting for their futures, and there are armies in the south that are a big problem - but I don't see a path for Russia to get what it wants. The question is how long will the sunk cost fallacy rule?