“To meet and overthrow the power of that dynasty, is the work now before all those who would prevent that consummation.”
If that was Lincoln’s announced intention, maybe he really did go to war to overthrow the pro-slavery constitution of the United States.
I note your weasel-word "maybe", necessary no doubt because most Lost Causers deny the Civil War was "all about" slavery.
Some claim it was "all about" money, others say that "Ape" Lincoln had... well, you know... "manhood issues", sort of like our current President wanting to build a "big beautiful wall".
So you certainly need a "maybe" there, if only to keep other Lost Causers off your case.
But the historical fact is that Lincoln did not in this speech, or anywhere else, ever propose to "start war" to abolish slavery.
In time he did use the Civil War for this purpose, in his words: