No, the US Civil War was not all about State’s Rights.
States Rights, cotton tariffs and free trade overseas were all major issues behind cessation by the initial states to do so. It was not the major issue.
The MAIN issue that caused cessation was whether the spread of slavery to all of the states would be allowed and the diminishing political power of the south to be tyrannized by the north. Slavery was the major issue. That is why the book “Uncle Tom’s Cabin” outsold every book in the USA up to that time, except for the Bible.
There were several reasons why the southern states got fed up with their declining political power and the increasing loss of autonomous control to the much more populous northern states, but the biggest reason for the Civil War was the issue of slavery.
It took me a long time and lots of reading to finally reach that conclusion after thinking for a decade or two that States Rights and cotton tariffs were the biggest issues.
It took a long time for you to form YOUR OPINION.