Main stream media is dancing around the issue without really stating it. A US minerals agreement with Ukraine is necessarily also an agreement with Russia, because the primary minerals of interest flow across the battle lines of the Ukrainian/Russian war.
Trump already had a meeting with Putin, so that those two leaders were prepared for a US/Ukrainian minerals agreement. Zelenskyy realizes that any functional agreement with the US requires peace with Russia, and sought formal promises from the US to back peace in the war, that the US is willing to fight with Russia to Ukraine's benefit.
Ukraine wasn't going to sign the minerals agreement without such formal guarantees. Ukraine should have made this known before the meeting. Instead, it attempted to extract guarantees from the US on the spur of the moment in front of the press reporters.
Trump may have wanted this scenario, in that it highlights that America is not going to send troops to Ukraine. This forces Ukraine's allies in the war to either put up, or shut up, on sending their own countries' troops into active combat.
Of course they don't want to send their own troops. Thus Trump has forced acknowledgement of a limitation to mission creep on the part of the West in backing Ukraine. Ukraine will have to cope with this. It also provides an escape hatch out of the war: Ukraine, Russia, and the US could become mining partners.