I think if someone wants to summarize Lincoln's views of slavery, it might be best to try not do it as a one-liner if talking about a timeframe across years. It's analogous to Trump and abortion. Today it's pretty solid that Trump is happy with the Dobbs decision and leaving abortion to the states and I think he'll keep that attitude.
But imagine FReepers a century and a half from now arguing, all with correct information (except in trying to summarize Trump), that Trump was "pro-choice in every respect", and he's "pro-life with the caveats", and "I hate the concept of abortion", and "there has to be some sort of punishment", and "the doctor or any other person performing this illegal act upon a woman would be held legally responsible, not the woman. The woman is a victim in this case as is the life in her womb." All before settling on the position Trump has today.
So I'll cut Lincoln some slack for going back and forth on different ideas on ending slavery, including the view he had when they tried multiple times to assassinate him in Maryland (the Baltimore Incident) before the Civil War (before Lincoln was even inaugurated). At that point Lincoln was telling the Marylanders that there was no need to join the Confederates because Lincoln would be happy just getting the federal govt out of the way and let the slave states have slaves while letting the free states be free. (Very much like Trump and Dobbs, yet the Dims tried to kill Trump multiple times.) Especially respect Lincoln's pressure of trying to end slavery, which had been a thing since Genesis, while also trying to prevent a civil war. (At least until the pro-slavery folks tried multiple times to kill him.)