Why are you conflating a win by Ukraine as marching into Moscow?
That is the thinking of people like Putin and his pals. Ukraine’s goal is for Russia to go home and leave Ukraine to the borders formally agreed to decades ago by Russia, Ukraine and the US in signed documents which included returning all the Nukes in Ukraine to Russia. Of course it is very hard for people with the Soviet mindset to imagine that Ukraine really means what it has stated as its goals.
I can smell your desperation.