That said, however stuffed as the boxes might have been there wasn't a shortage of troops, supplies, or officers willing to back that choice. If the fix was in, it was a popular fix all same.
There were constant shortages of troops and supplies in the south. All they really had going for them were their generals.
I had an history professor that maintained that at least two of the Confederate states had more volunteers in the Army of the Republic than they did in the Confederate army.
Not total number of soldiers, mind, simply the volunteers.
That there was that great a separation between the the leadership of those states and the hard scrabble farmers and miners that made up the majority of their populations. It was the monied land owners that wanted secession and the right to own other human beings as property.
The professor was from South Carolina, and was of the opinion that Lee should have been hanged, not for the war, but for continuing the war far past the point where the South had no chance of victory.
Revisionist history is a tempting fruit, but one best avoided.
As for whether the South would have been allowed to secede, had they not fired on Fort Sumter... I kind of doubt it, but a small island off of the coast of Maine did
de facto secede just a bit before the Civil War - an act not officially recognized by the US government, but recognized by the US Post Office, the Treasury Department (including the Coast Guard), and the draft boards.
Wiscongus remained separate from the US until WWII.... (A patriotic surge because of the war and an aging Postmaster led to the island rejoining the Union.)
Mind you, we are talking about maybe a couple of hundred people here.... Easy enough to ignore.
The Auld Grump - the one attempt by the draft boards to conscript soldiers during the Civil War was driven off by the wives of Wiscongous throwing hot potatoes at the soldiers....