Yes, that’s the way I feel in the end. I have to accept it, the evidence for it is strong, and yet I have this underlying discomfort with it because it’s so unlikely. A lot of science is like that for me too, where despite it being bamboozling and weird, scientists know their stuff and I have to trust them.
I truly don’t see why you think it “unlikely.” It seems likely to me. All the other proposals are “unlikely” to me.
There was apparently a fad for that kind of thing for a few years. Basically the equivalent of the spread of Lolspeak a couple of years ago. “Oll Korrect” was the contemporary “I can has?”
For this reason:
It’s the “Port Out Starboard Home” or “Gentlemen Only Ladies Forbidden” kind of explanation that is usually dismissed as nonsense. I always spell out the word as “okay” because the initials don’t feel right to me even though that’s apparently the right way to do it. I’d prefer a more interesting etymological path than a lame joke.
The first problem with the acronyms of Stack High In Transit or For Unlawful Carnal Knowledge or Port Out Starboard Home or Gentlemen Only Ladies Forbidden being the etymologies of those words is that there exist more probable origins for the words that the first letters of those phrases spell out:
https://en.wiktionary.org/wiki/posh
The second problem is that people before about 1910 basically didn’t create words in that way in English. Acronyms were rare in English before that point. In fact, it was World War II that caused the real growth in the use of acronyms. Note that O.K. is not an acronym but an initialism (i.e., the letters are pronounced letter by letter, rather than them being pronounced as the word spelled out by those letters). (Also note that some people use the word “acronym” to mean both kinds of word creation.)
One reason that the etymology of “O.K.” as being from “Oll Korrect” is accepted is that there is actually a reference to it in newspapers in 1839. There is no previous use of the term in any source. Reade shows that the term quickly grew after that point. The use of it for “Old Kinderhook” in the election of 1840 probably kept it going, where one might have expected it to die out like the other initialisms created around that time.