You’ve been told this before several times on numerous threads. The only way that slavery could be ended in the north was through the amendment process. Lincoln was not a dictator and could not just unilaterally end slavery. He did however encourage congress to write and pass such an amendment which did end slavery in the US.
But that is exactly how he did it. To count the Southern States voting for the 13th amendment as expressing their own will is just nonsense. Of course they voted for it, because they had Federal troops occupying their states who would not leave until they did vote for it.
But consensual it was not. It was a forced down their throat at the point of a gun position. You know, such as a Dictator would have done. A Fake vote with a preordained position put upon them by the man who controlled the guns.