No, it’s pretty well documented what he offered the southern states to prevent secession. What he offered them was keeping slavery which once again, they themselves stated was the reason for secession. It was about slavery from start to finish.
Not quite right. Lincoln himself, from day one and for years before he was elected, proclaimed that he had no power and no intention to interfere with slavery inside a state.
So he didn't offer to allow them to keep slavery. They already had that.
What he offered was that he would not oppose an amendment presently making its way through Congress that would irrevocably prohibit Congress from interfering with slavery in any state. IOW, no future amendment could change this.
This offer was rejected by southern leaders.