the argument wasn't that ukraine couldn't make breakthroughs. it was that it couldn't win, partially, which i still think is true but depends on how you define win. does it mean ultimate defeat of russia? because that is beyond ukraine and nato. does it mean taking the lost territory back? these questions were asked by very senior figures in foreign affairs from the outset. they weren't criticisms made by anti-ukranians. they were questions asked by people who wanted clarification over the kind of war their countries were dragging them into. the criticism was always the lack of clarity regarding the goal and ad hoc policy making. saying one thing which implied one level of support one day and another which hinted at something far larger and more escalatory the next.
i do think they're fighting russia to the last ukrainian but that doesn't mean that ukraine can't benefit from it. were the americans not fighting the soviets to the last afghani? did the afghanis care? so of course they're using ukraine. it's not a single-use kind of operation. the ukrainians aren't idiots. they know they have use-value to the west and they know their position. nato wants to fight russia via proxy. ukraine wants to fight russia directly. match made in heaven, no? it's not a contradiction, basically. my only criticism would depend upon what the west does over the next couple of years. not what it's doing now. what happens when the russians push back. and then ukraine pushes back. and on and on. all yet to come.
unfortunately i think this will be a massively drawn out war and last for years with the positions being unpredictable but possibly as they were before february.
the other thing is that if you think people making criticisms of the war are on russia's side, then you have, probably, been misled. some will be, for whatever reason which they themselves will scarcely comprehend, but most are not. most i've seen had almost no negative opinions of ukraine and almost no positive opinions on russia, but a highly critical view of nato. which i think is historically justified.