In fact, the script specified that it be pronounced “KAY-nar”: https://www.st-minutiae.com/resources/scripts/186.txt So that must have been forgotten/changed at some point, or maybe it is the auditory equivalent of “whisky” vs. “whiskey”.

Minor quibble (but then what other kind of quibble would it be):

In DS9: “The Adversary” the leader of the Breen Confederacy in the 24th Century is known as the “Autarch”.

Actually, “autarch” was the title of the Tzenkethi political leader, not that of the Breen. To my knowledge, the title of the head of state of the Breen Confederacy was never spoken (except perhaps in the form of Breen static).