Please feel free to elaborate.
Most successful efforts of guerilla warfare require the buy-in of the resisting population and some kind of conventional army that escalating threat to an occupier. The Confederacy had serious fifth column issues with unionists inside its own borders and of course, slavery itself. Former slaves aren’t going to agree with re-enslavement, and the next step of simply giving former slaves the land they’ve been working on if their former masters try to commit treason seems pretty logical.
The Confederates are fighting for slavery and can’t win.
The Confederates have made a case for secession if they believe that federal government is tyrannical and yet can’t tolerate counter-secessions made for identical reasons.
I think what winds up happening is that Alabama and Mississippi wind up becoming “Ex-Slave” states that pledge to support the Union out of a mixture of gratitude for their freedom and loyalty to a shared vision that black people are people too. Moderate places, like Virginia, probably give up; and there may be a prolonged resistance in places like the Ozarks and Texas; Stand Watie may well make it a threat in the West too.
And so, instead of the KKK being stamped out, you have Confederate Resistance being stamped out and the position of freed slaves rising as they are central to building a loyal America. Freed Slaves wind up becoming a pillar of Unionism in the South, and I think their position is well better than historical.