You said the war wasn't about slavery and immediately quoted this secession declaration:
"Our position is thoroughly identified with the institution of slavery — the greatest material interest of the world.”

Every other state secession declaration is similar and contradicts your thesis by not listening to what the secessionist traitors openly said motivated them.
You're writing mythologized history that's just an update of the Lost Cause nonsense that built thousands of statues of confederate generals to enforce the codified Jim Crow rule by racial terror that the Nazis copied.
https://link.medium.com/XSYFOHkbCAb