If you are arguing Ukraine will be "the war to end all wars", then you are correct. War and mankind are inevitably linked. However, if Russia loses the war in Ukraine and is forced to retreat to its borders, it is unlikely that Russia will initiate another war in Europe and most likely its future wars will be aimed at stopping encroachments on its southern and eastern borders.
Russia's manpower losses in the face of an overall declining population will leave Russia as one of the most underpopulated countries in the world and that will invite migration from east Asia, central Asia, and even the middle east. Some of its "neighbors" might see those migrating populations as the basis for claiming the land they have moved into.
And so, Russia will likely be on the defensive for the rest of its this century.
Russia should seek peace at whatever the cost and do whatever it takes to rejoin Europe. If it takes giving back all the Ukrainian territory it has lost, paying massive reparations in the form of energy subsidies, and turning over all leaders that participated in the crimes against humanity during the war, that would be a cheap price to pay for the benefits of not having to look over its shoulder at the West as it faces incursions on its eastern and southern borders.
Russia is going to run out of workers, fathers, and husbands before it runs out of "soldiers". Current estimates are that it has lost over 130K young men. Don't think of them as "soldiers" but workers. You can always drag up more soldiers, but eventually you run out of workers and in a population already declining at alarming rates, that is a disaster.
But the problem with peace negotiations is that it is unlikely Putin will survive such a process. His claim to power is that he has made Russia a "superpower" again... and defeat by a European funded Ukrainian army simply dispels that myth.
The west does not have an interest in seeing Russia collapse, but neither does it have an interest in seeing Putin prevail. There is little fear that Russia will escalate the war using traditional weapons and if it resorts to nukes, then Russia will cease to exist as a nation. On the other hand, the "proxy" war by the West in support of Ukrainians with their own proud history and traditions means Ukraine will eventually prevail with respect to recapturing their territory.
I am sure even as I write this response, there are people in key positions in Putin's regime that see that removing Putin provides the backdrop for ending the war and seizing power. How long before one of those people acts on this opportunity is the only open question. For that person, ending the war under the terms outlined above will be a reasonable cost to pay for becoming the "new leader" of Russia.
I am not advocating the US participate in regime change, I am arguing that the longer the war continues the more inevitable it will become, even now it might be too late for Putin.
