That's funny, I thought Zelensky was the one who came in calculating. He had already agreed to the "deal", but (a) insisted on not signing it remotely, but instead flying all the way to the US; (b) waited until he was on camera with Bush and Vance; (c) changed his tack and tried to get Trump and Vance to agree to more than what had been previously discussed, thus baiting them into confrontation; (d) hopped on a plane within 2 hours, when Trump had stated publicly "all he needs to do is come back and say 'I want peace'"; (e) headed straight to the UK where almost all the EU leaders were already waiting and had a photo op done.
It really looks like a carefully crafted narrative was planned and carried out to intentionally smear the current US administration.
Everything up to your last bit about smearing the US is not wrong. As you said, Zalensky insisted on flying in to make the deal, then stepped over the line relative to the original deal they were meant to be doing.
I don't think there's any smearing attempt on Zalesky's part though. Contrary to Vance and Trump's assertion, Zalensky has thanked the US a lot of times. He wouldn't be wanting to smear the US. Trump did begin the meeting diplomatically, it was going fine, he even complemented Zalensky's outfit. Then JD opened his mouth!
It's hard to know for sure what's going on, which may be the point. The theatrics of argy-bargy is like a smokescreen.
It really looks like a carefully crafted narrative was planned and carried out to intentionally smear the current US administration.