It is settled in a sense, that there's no solution besides destroying Russia as a state that would result in return of Crimea to Ukraine. As OP said, whether we recognize Crimean referendum or not, is irrelevant, so bringing Kherson into conversation does not make much sense. Polls in territories occupied after 24.02 would not show the same level of support of the referendum results, as it happened in Crimea.

And what's the problem with destroying Russia? Hitler Germany was destroyed for pretty much the same. Or should US wait for another Holocaust again?

Referendum will not happen due to the low support of Russia in Kherson. The situation is not the same as it was in Crimea in 2014.