The new smaller countries wouldn't have developed a transcontinental economy and might well be poorer. Government could be more powerful in some of them, as it is in Canada and Europe. Racial conflicts would make life in the Confederacy turbulent and hazardous.
Along with all of our problems, America did benefit from being top country for a century in ways that we take for granted now.
I think they would have done, and I also think mores states of the Union would secede and join the confederacy after the initial question of secession was settled in favor of the Southern states.
The new smaller countries wouldn't have developed a transcontinental economy and might well be poorer.
No guarantee that they would have been poorer, they might have been wealthier. All that blood and treasure expended in trying to maintain independence would have gone to more worthwhile pursuits.
And a transcontinental railroad was inevitable. I've seen people allege that the Railways act of 1862 was just a payoff to Lincoln's powerful supporters in the railroad industry.
They were certainly given immense wealth to build those railroads.
Racial conflicts would make life in the Confederacy turbulent and hazardous.
That is an area in which things might not have turned out better.