Davis refused until the last days of the insurrection to allow slaves to fight for the South.
Like almost all Slavers he feared arming the slaves because he knew what would happen.
You claiming he did not fight the insurrection to preserve slavery is not even good sophistry and needs no response. His words speak for themselves.
Slaves had been fighting for the South from early on. Davis had supported it. It was the Confederate Congress which opposed it until later in the war. Of course the Confederate Congress did not have the power to dictate to individual states who could serve in the units they sent and Confederate commanders in the field often accepted any Blacks be they slaves or freedmen who agreed to serve.
You claiming they were fighting to preserve slavery when Davis said they weren’t and when they were offered slavery forever by express constitutional amendment just shows what a joke your argument is.