The 350 billion dollars is a lie by Trump, we haven't even given half of that. It is also worth noting that our European allies have given more than we have -- and far more if you go by per capital payments.
It is also worth noting that not that much money has been sent to Ukraine. For example, most of the military aid given has been given to US defense contractors; either we shipped old equipment (such as the Abrams M1A1) and had contractors build newer replacements (like the Abrams M1A2) to replace what was shipped, or they built things like artillery shells (after we depleted our older stock of munitions) and sent it directly to Ukraine.
Most of the rest of the military aid to Ukraine was paid to the US military, it was paid for US military members to train members of the Ukrainian military and house and feed them during training. Of course, the US has also benefitted from what our European allies have sent to Ukraine -- such as with the F-16. The US has not provided any F-16s to Ukraine. Instead, it is the Netherlands and Denmark that have supplied the F-16s; and the US has received contracts with both countries to replace the F-16s they are giving to Ukraine with US built F-35s. Additionally, two more countries, Norway and Belgium, have stated they will supply Ukraine with F-16s (again, those planes are being replaced with F-35s).
You mean, all Zelensky had to do was give Trump a blank check -- give Trump the minerals he wanted from Ukraine (worth far in excess of what the US has given Ukraine) but not have any promises in return. Zelensky had always maintained, even before coming to the US, that there had to be security guarantees.
Unlike most in the US, Zelensky remembers that the US promised to defend Ukraine, if Ukraine got rid of its (the Soviet Union's that were located in Ukraine) nuclear weapons. Since that was merely a verbal promise, and not one put into writing, American Presidents have been ignoring it for more than the last decade. Zelensky is not going to make that mistake again, this time he wants protections spelled out in writing -- because history (at least Putin's history while in power) is that he will rebuild his army and attack again once they are built up.
Despite Zelensky always stating that he needed security promises, to keep Ukraine from attacking, Trump would not put them in writing (essentially not giving any type of security or aid promises, at all). It was the Trump White House that changed the deal, from what had been agreed to, and just wanted Zelensky to "trust them."
It is also worth noting that, in the aftermath of the meeting,
our allies sided with Zelensky (there are more statements, but that article has a nice selection). Many also mentioned how the US is no longer a reliable partner and that they need to find a new leader, since the US can't be depended on.
It also begs the question, how did Russian state-owned news,
TASS, get into the press conference in the Oval Office? The Trump administration won't even let some news agencies like AP and Reuters into the White House, but somehow Russian-state media not only got in the White House but into the Oval Office, to see Trump and Vance belittle Zelensky. This is definitely the type of thing that makes it appear the berating of Zelensky was done intentionally.