There is no winning or losing in 21st century hybrid war between to states. THere is no natural offramp and the capitulating blows are stayed to the point that it doesn't "escalate".

In that light, it's not many leaps and bounds to assume that of the two, Russia is certainly "suffering" more in the grand scheme when viewed from the perspective of sunk cost fallacy. Their goal was to blitz the country in one month. 4 years later, Half a million confirmed dead, no western support, endless sanctions directly affecting the working class. That working class has been in a war economy against a foe who's GDP (nominally, no outside help considered) is 12 times smaller than it.

Naturally this is not ideal, and on the other side, Ukraine has suffered massive territory and personell loss. But having the world "behind" you and not needing to support a gargantuan economy/civil base allows them to always "spring back" more. Esp with western assistance, and especially if there is still territory to defend.

of course, all of this is moot if Russia ends up controlling ukraine. But at current pace, it will take roughly 10 million dead and 20 more years (minimum) of this form of warfare for ukraine to "fall". THat seems like losing.

Unless they do a general mobilization, they've already lost. They can hit Ukraine with missiles, but they're losing territory and their rate of attrition is extreme. If they do a general mobilization they might beat Ukraine, but that will likely result in a full political collapse.

Where are the goalposts for "losing"? Is "not winning" considered the same? Because the "three day to Kiev special military operation" has turned into a 5 year war with very little progress made in terms of conquering Ukraine.

Running out of men and material.

When they have to conscript in Moscow Putin will be in trouble.