Was it really a set up? These whitehouse visits by foreign leaders seem to follow a set format - actual discussions happen prior or behind closed doors; pretend discussion staged in front of the press in the oval office, then final press conference with both parties putting a nice bow tie on things (as per macron and Starmer).
Obviously what we just saw was a departure from this, but I don't for a second believe we were watching something spontaneous.
It's either a way for zelensky to bow out with pride intact in the face of a sell out of Ukraine, or he had gone toe to toe with trump over the mineral rights and demanded more in return than trump will give (not unreasonable). Either way we were treated to showbiz rather than a public spat.