It looks like the US wants a regime change in Ukraine, it's possible that this became a pre condition from russia for talks to go forward. OTOH, a minerals deal with the US ensures that the US will have a stake in defending the postwar ukraine. Lots of drama and optics involved for sure, but it seems the outcome or the talks was predetermined JdVance will not last for long - is there procedure to replace him?
Why would he "not last long"? Who would remove him? Would they not also remove Trump if they could remove Vance?