Lincoln is probably the closest president to being a tyrannical dictator the US has ever had. He did whatever he wanted and pretty much totally ignored the constitution in so many ways. Lincoln's history was definitely washed to be much better than it was.
https://www.amazon.com/Lincoln-Unmasked-Youre-Supposed-Dishonest/dp/0307338428
You're conflating issues, really, and have no historical basis for your positions.
Here is a fantastic book on Lincoln and what kind of man he was.
Lincoln Unmasked: What You're Not Supposed To Know About Dishonest Abe
I'm not going to sit by while you repeat things your government teachers told you.
The letters written by the southern soldiers and their commanders tells a wholly different story about why the war was fought.
It was a war to defend their countries (i.e. the states.) The Constitution was ratified separately by the 13 countries (the word "state" at that time was used to describe places such as France, Spain, etc.) coming together.
If they were not separate countries, they would have simply held one ratifying convention in a chosen national capital, and that would have been it.
Again, the reasons for secession are not important, as the legal and moral basis was sound all on its own. The north instigated and provoked a war to justify imprisoning the people of the south into a union which they wanted no part.
For less than the cost of the Civil War on the North's part, they could have offered the slave owners double to triple the value of their slaves. England ended slavery without a civil war, and so could of Lincoln. He simply was blood and power hungry.