“A more high profile example is the heroes’ welcome received by Burnside as liberators of Knoxville.”
Knoxville, TN was a divided city, with half its citizens remaining pro-Union and half alligning with the Confederacy. Tennessee itself, of course, seceded. I equate the pro-Union sympathizers in the same light I view thge Sudeten Germans in Czechoslovakia in 1938. The Sudeten Germans welcomed the Nazis as liberators, but they were hardly representative of Czechoslovakia as a whole, just as the pro-Union symnpathizers in Knoxville were not representative of Tennessee. I alluded to this in an earlier post.
It is a mistake to assume anecdotal references bespeak a larger sentiment, as you are doing with the Knoxville illustration.
The Sudetenland example is a very well thought-out analogy for your point, but I think an examination of the secession election returns for the broad East Tennessee region suggests a scale of widespread sentiment that differs in quality from the narrow ethnic Sudeten element. And all over the South there was a seed of latent Unionism from the beginning which later gave rise to the fatal level of southern disenchantment with the Cause.