Honestly, after watching the full press conference twice, I suspect this meeting will go down in history as a canonical example of "what not to do as a politician".

It seems Zelensky was unaware he's dealing with Trump, his demeanor, and his presidency. Historical this or that is not applicable when dealing with someone like him. Trump will be Trump, and nobody should expect otherwise. Always best to understand and know your counterpart.

I'm definitely no Trump supporter, but objectively, prior to the blow-up, Trump was being somewhat reasonable. Maybe the most Presidential I've seen him. He reaffirmed support for NATO, continuing sending weapons to Ukraine, and generally wanting to push efforts to stop fighting, etc. He respectfully let Zelensky speak numerous times, at length, on difficult subjects, even things he didn't agree with. He even respectfully looked at photos of prisoners offered by Zelensky. Compare that to his prior behavior with the UK Prime Minister just a day before where he cut him off numerous times forcefully.

Zelensky made numerous mistakes, emotionally reacting and replying to reporters questions when not directed towards him, adding on more grievance, and generally not being as a politician needs to be. He clearly showed why being emotionally responsive doesn't work in a debate, court, or other significant and crucial meetings.

The supposed Mineral agreement may just be a way for Trump to look like he got concessions or something in exchange to look strong to his supporters, especially compared to his favorite archrival Biden.

If Zelensky had goals/aims he wished to reach, he should've done his best to ensure the truth and his viewpoint comes through when is applicable to the question being asked, but not offered voluntarily or in conflict with his ally's statement. His demeanor from the beginning of the broadcast was already chilly and stern. He should've let any need for venting to come out AFTER the signing, at the 2nd joint press conference scheduled for later in the day.

If you watch Vance's initial statement, it was relatively supportive of Ukraine and leaned to neutral at the end. Nothing negative outright that needed to be added on to. Zelensky erred here by asking if he could ask Vance a question afterwards which led to the blow-up and escalation, and ultimately really bad decision of telling Trump he's going to feel this or that. This was a classic mistake. Question was over, should've moved on. Logically no possible statement could've helped his efforts or goals, so he only had the potential to hurt himself. Further being emotional, combative, and from Trump's perspective, relatively disrespectful did not help him. The entire over answering, and combative escalation was an emotional release from Zelensky and did not aid his aims, and ultimately hurt him.

He left in the worst possible position. He didn't get to his signing, nor his second opportunity for public statements post-signing, where he would've had clear gains, while forcefully stating whatever truths he feel were being left out or gaslit.

It seems Zelensky felt he needed to vent and express his people's pain, frustration, and anguish, but as the saying goes, time and place for everything, and unfortunately wasn't correct for either.