I think if I were to summarize the "Russia is failing" narrative it's that Russia expectations of a quick, easy victory were completely unmet, and now even if Russia does want to occupy Ukraine it's not going to be the quick and easy decapitation strike that they thought it would.
So your argument is you assume Russia wanted to take Ukraine in 100 milliseconds, and if people can't prove you wrong you win?
I'd actually like to read more of this, if you have happen you have a source at hand.
https://www.reuters.com/world/us-believes-russia-planning-de...
https://www.freep.com/story/news/politics/2022/03/05/ukraine...
https://breakingdefense.com/2022/02/russia-aiming-to-decapit...
https://www.axios.com/russia-seeking-decapitate-ukrainian-go...
https://www.businessinsider.com/russia-invasion-of-ukraine-w...