Here's why that's not true:
So sure, you can say "Confederates didn't want Northern conquest", but the Confederacy officially claimed three Union states (Kentucky, Missouri & West Virginia) three Union territories (Oklahoma, New Mexico & Arizona) and sent military forces into eight others.
That helped make the Confederacy an existential threat to the United States.
central_va: " Face it Lincoln's war was optional and he could have both prevented and stopped it at any time.
He didn't want to."
And Jefferson Davis could have ended his war on any day before April 9,1865 with much better peace terms than he fought on & on & on to achieve: Unconditional Surrender.
But, as you said, he didn't want to.
Good God nobody in the South thought the South could conquer the North. Like I said that is preposterous. The North had 3 times the people and all the industrial resources it needed. Everyone knew that then and knows that now looking back.