What would the US be like if the South accepted a buyout of all the slaves? That's billions in today's money saved and 750k white men in the prime of their lives who survive and procreate. Also no Reconstruction and no 14th amendment that wildly expanded the federal government's powers.
It is difficult to imagine a realistic scenario where both sides would be reasonable. The number of free states was set to exceed the number of slave states, the south wouldn't allow that and the north wouldn't back down. Even if the south accepted something similar to Britain's Slave Compensation Act it would be difficult to enforce unless they were totally crushed as they were in real life, rendering compensation pointless. Further the political institution of the south would still exist, just without slavery as the defining issue, they would probably demand more new "jim crow states" in the west and undermine federal authority or secede, which may in turn escalate to war.
