Ukraine

Russia still has a large airforce, the navy outside the Black Sea has also not been hit and the nukes also still work. All of that is with an army, which is clearly able to fight a large scale war. Obviously they are so far failing to take a country with a quarter of the Russian population, but they are clearly able to fight.

What this does do is destroy the massive Soviet era weapons stockpile, it hurts the Russian economy and kills a lot of the willing fighting age men. If Putin is removed and Russia and the war ends, chance are that Russia ends up in a huge economic crisis, with a lot more of its talent leaving the country, massive cuts in military spending and the demographic crisis becoming even worse. It probably means a lot of infighting, maybe even a civil war, but certainly a lot of crime. However Russia as an entity will survive this and will remain a threat to Europe, as long as its culture does not change.