There were aspects of the CSA secession that were worthy of consideration and also justifiable constitutional changes in my opinion that would create a legitimate limited government, states rights, term limits, and other economic improvements and localized responsibility
I understand you recognize the importance of slavery in the secession, and I appreciate you saying so. But I think you give too much lip service to the supposed ideals of the CSA. I think those were never actual ideals, but rather just temporarily convenient tactics for the promotion of white supremacy.
Take states rights, as an example. The pro-slavery factions liked to talk up the importance of states rights, but did they believe in them? Well, look what position they took when the question was fugitive slaves. A true states-rightser would have taken the position that each state has an absolute sovereign right to decide whether or not slavery exists within their borders, and so once an enslaved person crossed into a free state, he became free, and the free state was under no obligation to shackle him and return him to someone in another state who claimed ownership rights. Yet these supposed states-rightsers cheered the federal Supreme Court effectively extending slavery, by federal fiat, into every free state, for purposes of dictating the status of fugitives from slavery.
Similarly, the confederate states talked a good game about limited government, but it was the CSA, not the USA, that was first to institute a draft, during the war. The CSA was also more heavy-handed in dictating economic terms to its component states for purposes of the war effort. Once again, when the issue came down to a choice between their so-called principles and whatever was convenient for the cause of white supremacy, they always went with the latter.
I can praise the courage of the thousands of Confederate soldiers that went off to war and also praise their families for enduring their absence or loss.
I don't deny their courage, nor the hardship they made their families endure for their cause. But couldn't the same be said about most soldiers in history? Is it right to praise them for those things, even when their causes were monstrous? For example, it's hard to deny that the 9/11 hijackers had a level of courage that would put most soldiers to shame. How many soldiers, after all, have ever willingly gone out on a mission that they knew, if it succeeded, would give them zero hope of surviving to see the end of the day? Other than a handful of kamikazes and suicide bombers, that certain embrace of one's own death for a cause one believes in is almost unheard of in war. Yet, while I cannot claim to deny their courage, I can't praise it, either. The same is true for the Germans who defended the beaches of Normandy -- seeing wave after wave of allies hitting the beach, and knowing that if they stood their ground they'd almost certainly be dead by nightfall. There was certainly courage in that. But it was courage in an unjust cause, and so I cannot praise it. For the same reason, I cannot praise the courage of the confederate soldiers.