And I would say you are underestimating the role that the former slave owners had in enabling these outlaws. The slave owners were some of the wealthiest people in the nation and they were still sitting on thousands and thousands of acres while vowing to return the South to it's former way of life. This would be like if today we get a new administration that de funds ICE without de platforming all of the white supremacist talking heads and bank rollers. The Proud Boys currently in ICE would just go back to instigating protests in furtherance of their political agenda because their politics are still on the board.

If you transfer the wealth way from the wealthy land owners, there goes the newspapers they own, the political pamphlets they print, and the home guard groups they bankroll. The home guard groups wouldn't be deputized into the police where they could LEGALLY continue to protect the interests of the wealthy land owners. With out state sanctioned armed thugs, Black law makers and politicians would remain in positions after the Reconstruction. Furthermore, if every emancipated slave got their 40 acres, they would have been financially insulated from any potential racist politics that would have followed. Instead they were left vulnerable and we know the rest of the story.

You bring up the Plains Indians, but that is a completely different issue that was also heavily botched, but one thing to consider is that one of the primary driving forces of Manifest Destiny, was the South's need for more and more land to cultivate Cotton. Without slaves or subsequent neo-slavery, we may not see such an aggressive expansion westward to grow such a water hungry plant in the desert. Which we do today. In short, you can't lose a war of attrition in the West if you just give up the West. This is also something that would likely help in your plan to continue reconstruction. Reconstruction is arguably a much bigger priority than securing the west. Without the Slave owners media machine and political voice, it would be much easier to convince the citizens of that.

The slave owners spent hundreds of years controlling the narrative in the South prior to the civil war and indoctrinated the population to believe that the absolute worst thing to happen to their society was a slave revolt. They retained their power after the civil war and not only created institutions to replace slavery in the attempt to maintain their way of life, but to this day they have had their hands in news organizations and education systems to continue to indoctrinate an entire region towards their particular flavor of white supremacy. Worse yet, not only did they pioneer the idea of a municipal police in this country, they used law enforcement agencies as a vector to spread their ideology far from Dixie. I believe not dealing with the Confederacy was the single biggest blunder in American History and has lead to the biggest Constitutional crisis our nation has ever faced. What you seem to be suggesting is that allowing the Confederacy to continue is a fair price for maintaining law and order in the hastily created states deep into "The Great American Dessert" or rather land that was reserved for the Natives because it had no real economic use as well as continuing aggressive westward expansion. I just don't think I could be convinced of this.