I believe the problem for Putin is that the hearts of the soldiers cannot be mobilised in an unprovoked attack on another country than when it was their actual homeland they were called to defend.
It's certainly harder to motivate people for something like that, but this is also a problem Putin has exacerbated by his own actions. This isn't a war, it's a "special military operation". That distinction matters. And he didn't make that distinction because he's an idiot, but because it's part of a bigger strategy for maintaining power: cultivate apathy. Russians are politically apathetic, by design.
Unlike Hitler or Stalin, Putin doesn't actually want the public to be radicalized. He wants them to be detached from politics. And it's a strategy that made a lot of sense. The idea is that a politically apathetic public will simply let Putin do what he wants to do, because they don't feel like they have much stake in the details of politics. And that strategy has worked. Political opposition to Putin can't gain traction, because mostly people don't care.
But that kind of apathy also prevents serious national mobilization of the sort you're describing. Stoking nationalism carries serious risk for Putin. It would help with the war effort, but if there's no payoff, no victory to justify the sacrifice, all that patriotic zeal could easily turn against him.
The problem for Ukraine is that Western support might eventually vane as the war drags on.
Ukraine is in a good position, but with the enemy occupying that much land, I don’t think we can say that the position is incredibly good. The more time passes, the Russian position at the negotiation table improves, if the Russians can hold on to the occupied land.
I'm not sure time is really on Russia's side. If western support drops, Ukraine is indeed in trouble. But there's only two countries whose support is indispensable to Ukraine, and that's the USA and Poland. The USA because we've got the most weapons and money to give them and the most intelligence assets (read: spy satellites), and Poland because they provide the critical logistics link to get aid into the country. The aid of other European nations is helpful (sometimes
very helpful), but Ukraine could keep fighting without it. Poland is in this for the long haul, their support is basically guaranteed, because they hate Russia with a white hot passion born of bitter experience. US support is likely to remain strong too. We are in many ways "war weary" from our involvement in Iraq and Afghanistan. But no US lives are at stake here. And that makes a huge difference. I don't think US support is waning.
Russia has plenty of manpower to call upon if it needs to, though there's a price to doing so and they may not ultimately be willing to pay. But they are constrained on material. They're losing equipment fast, and I don't think they have the industrial capacity to produce more at the same rate that they're losing it. And this isn't like WW2, they can't just convert tractor factories into tank factories. They need (relatively) high tech weapons, and their production capacity on high tech weapons was kinda garbage, even before the war. And sanctions have made that worse. If they dip too deeply into their stockpiles, then they're going to destroy their ability to defend themselves anywhere else. And Russia has far more enemies than just Ukraine that they worry about.
Already we see calls for the two parties to negotiate, and presently that can only mean for Ukraine to accept status quo.
I'm not sure that's the case. From a strategic perspective, now is probably the best time for Russia to negotiate while conceding the least. As time drags on, I think their position will deteriorate, and they will have less and less to bargain with. The problem with negotiations right now is that Ukraine feels (probably correctly) that they don't have to concede much, if anything, and Russia doesn't yet realize that it will be forced to concede quite a lot.
