I'd be fascinated to see how many people posting here have actually watched the full press conference.
Zelensky really couldn't have played this any worse. He directly started the confrontation with JD Vance with his response to a fairly inconsequential remark about diplomacy, and it went downhill rapidly from there. It was completely unecessary. He can't change who the POTUS is for the next 4 years, and needed to confront this reality by managing Trump in a way that benefits Ukraine.
IMO he missed a golden opportunity to manipulate the situation and put Trump's entire reputation and legacy on the line with regards to future "security guarantees", on camera, in front of the entire world.
He should have gone out all guns blazing in terms of effusive praise and thanks for Trump, his administration and the American people for their support, and their prioritisation of helping them end the war. He had 45 minutes to make Trump feel as good about himself as he possibly could, get everyone in the room worked up and jingoistic. You can do this without agreeing with any of his politics whatsoever. He's like a 5 year old child and as easily manipulated as one with the correct strategy.
Once he'd got the room onside then he could have quite simply addressed the security guarantees that Trump had stated about 5 times during the conference he didn't want to talk about.
"In terms of the security guarantees we have been asked about earlier. Let me ask you all a question. And I'll let you into a secret now, its a rhetorical one.. Once we have a shared and substantial economic interest in maximising the extraction of our vital natural resources...
Does any person in this room, or even the planet, think that Donald Trump; the man sitting next to me, the most powerful man on earth, is the kind of man who will let someone come and take these from him? Run tanks and drones through the infrastructure his money has been invested in? Let the lives of American people he has trusted to do this for his country come to harm whilst doing so?
Once this deal is done, it's just a matter of ironing out the specifics."
Job done. Communications from diplomats involved clearly imply this is how the deal was being thought of, so to come out and say it like that puts him exactly where you need.