For the cost spent? The clay in question isn't worth it.
And these are largely immaterial points.
For domestic political reasons, Russia has to win. There is basically no conceivable situation where Russia can fail to "win" and handle the domestic political fallout.
So the starting point for any potential peace deal has to be "Putin and Russia can credibly spin this as a win worth the cost paid to achieve it".
Ukraine turning into a generation of insurgency hell? An acceptable cost for Russia if it can point to some tangible gains.
The West is left in the unenviable position of not being able to win. To get a win, NATO has to intervene militarily. And that is WW3 with all of the consequences of that fiasco.
It doesn't really matter how much in terms of small arms the west pours into Ukraine, all that does is make the outcome bloodier for Russia. It does nothing to change the underlying fundamentals of the conflict.
Russia won't touch a NATO member, but short of that? The borders will end up wherever Russia wants them. Which means that if the West wants those borders to be somewhere short of the current border between them and Ukraine then they have to give Putin something.
The only things of worth in Ukraine from the Russian point of view are the geographical features that block armies. So yes, the Dnieper is one of the single most important features in the entire nation.
The Dnieper isn't some small stream, it's a wide, deep, fast moving, river with relatively few bridges across it. There are less than twenty of them along the rivers entire length. That part of Ukraine has the Sea to the South, the River to the west, Russia to the East, and Belarus (Russia) to the North. Locking down the borders against effective smuggling is viable and not that expensive or difficult. Can it be perfect? No. Can it be good enough to make keeping a sustained insurgency active and supplied effectively impossible? Yes.
Once those borders are secure, Russia can park basically an entire army on the territory and get to work suppressing/integrating the populace.
It's West of the Dnieper that a Ukrainian insurgency really becomes hell.
Ukraine won't be allowed to join NATO, whatever happens. Even if Russia pulled out, if it was announced then it would be WW3 the next day because Russia would flat out invade Ukraine and dare the US to honor Article 5 under explicit, public, threat of nuking New York and DC.
I really don't think you get how much Ukraine in NATO is a redline for Russia. Not for Putin, not for the government, but for Russia as a collective whole. It is very much a "we will nuke you if you do this" redline.
This war in Ukraine isn't Putin looking for an "out". While the exact severity of the sanctions might be a surprise (and I wouldn't bet on that), no level of sanctions are enough to alter Russian thinking on this invasion.
So what comes next? What does the West do after Russia has grabbed off however much of Ukraine it wants and held "free and fair" elections to vote in a puppet government to legitimize the whole thing. The West recognizes a government in exile perhaps? A government that holds none of its claimed territory is not a government, it's a joke. I guarantee you that China and India won't recognize the exiled government.
Russia still has all of those commodities, it is still a nuclear power, it is still sitting right there on the Eastern edge of Europe, it still has one of the world's most powerful militaries.
It's not just some minor irrelevant nation that can be ignored for years or the like.
And it is also self sufficient in its critical areas. China can be destroyed in a month by stopping oil flows from the ME to China (which anyone with a blue water navy can do with impunity). Its economy can be crippled overnight by the simple expedient of refusing to allow its goods to be exported. Its population can be faced with starvation in relatively short order.
Russia doesn't share any of those weaknesses.
So Russia takes Ukraine, and what happens six months? A year? down the road.
I mean US domestic politics. Biden has staked out a strong position on stopping Russia from seizing Ukraine. Russia has eight months before election day to have achieved a "victory" sufficiently unambiguous that Biden is seen as having failed.
Eight months where US gas prices are through the roof. Eight months where Republicans are running on the claim that the reason that Russia can get away with all of this is the Democrats green agenda (vote Republican and we will bring down gas prices). Eight months where Europe deals with the political upheavals of a resurgent Russian threat.
And then two years after that, you have the Presidential election. Where the Democrats have Ukraine hanging around their neck along with all the other fall out from it.
There is still a very large vein of support in the US for going fairly isolationist. Tapping into that and running on a platform of "The Democrats want to bring back the Cold War and risk nuclear annihilation to protect Europe" could easily happen. Especially if Europe stops standing firm.
