One rule. If you know that you are not personally liked, don’t dwell on a person’s nerves. Zelenskiy knew that he was invited to the Oval Office because of the deal. He tried to make it about everything else before the deal. So it happened as it did.
It became an issue of personalities. Trump who is blunt essentially said, you have bet on Biden last time, now I am elected (he said something about all the counties turning red), and with me, the rules are different.
I think lengthy meeting was unnecessary given the prior history. You came, you sign, you leave. The problem is, even some Ukrainian commentators say that at European meetings, there is some cross of boundaries by Zelenskyy (like, not taking an interpreter). Here, whatever he did, was viewed as boundaries crossed.
And I yet haven’t made up my mind as to why Vance intervened.