It depends on the goal. His goal to wreck Ukraine and its economy has succeeded. Important infrastructure is destroyed (either by the enemy or in defense) as multiple airfields, factories, power plants, ports are in ruins. But the Russians anticipated a quick victory, basically by using their pro-Russian factions and saboteurs already in Ukraine to sabotage the defense and hitting Ukraine's bases in a 'shock and awe' manner. Then the cannon fodder would come in to bog down the Ukrainian army and keep 'order'. During that distraction special forces would aim to capture and control key targets such as the leadership.
The first action is failing because of social media. The Ukraine MOD has put out this simple instruction: "If we can see it, we can destroy it. If we can't see it, tell us where it is". Often troops show up disguised as Ukrainian units that are quickly destroyed or arrested. They have basically enlisted their entire population to keep track of the Russians. Plus they've received significant intel from the UK and US about Russian plans and movements.
The second action was limited because Russia does not have a large stockpile of precision weapons that the US has and more importantly Ukraine hadn't yet mobilized. Russia destroyed barracks, military installations and air bases which were mostly still not fully staffed. The attacks only boosted morale of the soldiers still home or already entrenched in the East.
The cannon fodder rolled in with their columns, poorly supplied and mostly confused. They were called up for 'exercises' and suddenly find themselves in war. Being berated by the elderly and shot at by angry Ukrainian forces. What they find is not what they were told: to be received as 'liberators' ending a genocide. This has made the job of the special forces speeding towards more important targets much harder as the Ukrainian forces have not been demoralized, spread out or worn down from the fighting. Far from it. They've also not launched reprisals on the Russians living in Ukraine, in fact they hand out weapons to anyone willing to fight for their homes.
So the Russian cannon fodder is now mostly stuck outside the cities in the vast empty steppes without fuel like the Wehrmacht was or fled into the woods surrounding Kyiv and other places. Elite units were either taken out or never managed to land.
A limited failure on the part of Russia could however also backfire. As it supports Putin's claim that Ukraine was heavily armed and thus a threat to Russia.
They're now sending in the Chechens which are brutal fighting machines. Chances are they can force a breakthrough in Kyiv. The Russians have already started to claim 'false' victories and captures as they need something to boost morale and heroic stories of how they fought the Nazi's. So far only stories of the Ukrainian Reaper, who shot 20 Russians, the Ghost of Kyiv who shot down 5 planes with an obsolete Mig-29 and the soldier that defied a Russian warship by telling the captain to go fuck himself are making the rounds. Not to mention Zelensky who has become a symbol of the fight for democracy agains dementia and tyranny. The old vs. the new.
On the long term though Ukraine is fighting on 4 different fronts, which is not sustainable. And so far the Russians have decided not to attack cities in full force like they did in Syria and Grozny.
For their standards the Russians on the ground are pretty careful in their operations and partly because they see this as a mission to free their brothers from an evil regime.
This is why Macron predicts a long war because the Russians can move slowly to 'liberate' Ukraine town by town, street by street and reinforce the border areas they've captured like they did in the Donbas.
Creating an ever smaller pocket for Ukraine to defend in a war of attrition they can't afford.
