To be clear: Are you saying the North was fighting to end slavery and the south was fighting to keep slavery?
It would be fair for both of us to be clear.
It appears that you have conceded that Texas, the subject of this thread, said in its ordinance of secession, that it was seceding because of slavery. Also, that several other states of the Confederacy said this in their ordinances of secession and/or statements of causes.
You cite an ordinance of secession from Florida that is silent as to cause, but have not identified a source that gives a cause or set of causes for that state.
Here is my position:
Generally, people argue as to extent to which slavery and the conflict between the industrial north and the agrarian south were causes. I’m not going to be able to resolve that. My position is that there two causes, and I can cite observers of the new country who saw these conflicts well before the war. Alexis de Tocqueville, in his travels in our country in 1835, I think, saw these two conflicts. This is about as clear as I can be about the south.
Regarding the north, initially the response of the north to secession was to avoid striking at slavery on the hopes that a terrible war could be avoided. The Republicans barely held onto the House in the midterm elections of 1862, and this was without the representatives of the Southern states. Lincoln was desperate for a cause with which to rally the north to a long and very costly war of attrition with the South. “Preserving the union” was not a sufficient cause. So, following a claim of victory at Antietam, Lincoln issued the Emancipation Proclamation, freeing the slaves of the areas in rebellion, and offering the enlistment bonus to owners of slaves in the areas loyal to the union, if the men among those slaves joined the union army.
To complete the picture: The provision in the Emancipation Proclamation providing for a form of compensated emancipation in the areas loyal to the union, along with the state initiatives in Kentucky, Maryland and Missouri practically ended slavery in the country. Delaware debated the justice of ending slavery when most of the few slaves of that state were old and were being taken care of by the masters as was part of the deal that slavery involved.
While there were many aspects of the movie Lincoln starring Daniel Day Lewis that I enjoyed, it was wrong as to actual history of the 13th Amendment. The only disagreement in Congress concerned whether the 13th Amendment should be an abolitionist amendment or whether it should offer compensation to the few remaining slaveowners loyal to the union.