Lincoln was never President of Texas. James Buchanan was President when Texas seceded, and Andrew Johnson was President when Texas surrendered to the armies of the night.
Texas never left the Union, since the United States didn’t recognize the secessionist temper tantrums. Texas malcontents knew Lincoln was assured of election and just days before his official installation as president, Texas pitched their largest fit. Buchanan didn’t recognize the secessionist claims, either.
The Confederates lost. Deal with it. The Confederate BS parade is a farce as most Americans dismiss the lost cause rantings of bigots and inferiority complex sufferers for what it is.
The war’s been over and done with for 145 years. Lee recognized it for what it was and championed a return to normalcy as a whole and indivisible nation.