My take is that Vance should have kept his mouth shut (but I understand his being upset) and Z would have been much better served to have just said something to the effect that he appreciated all the US has done to help his country and looked forward to listening to more of President Trumps ideas over lunch...
Evidently (and for good reason) Vance holds a grudge (from Z basically campaigning in PA for slow Joe) and has heard far too much coming from Z in regard to what He wanted..., with little appreciation for what's already been done for him.
Much like what happens here routinely, they started talking past each other with neither grasping what the other was actually saying..., at the point when Z began attempting to give Trump a history lesson on the conflict and warn we would eventually "feel" the force of Russia in the future... (none of which was technically wrong) then Trump became incensed, pointed out that without our $ and gear they'd have been cooked... (which was also accurate) at which point discussions were basically over...
Z is a wartime leader, he's no statesman (personally I admire that about the guy). Trump isn't much of a statesman either, he sees himself as an advocate for the U.S. (and personally that is exactly who I voted for)...
Unfortunately for Z, Trump does have the winning hand in this game... Trump sounds like he wants an immediate Cease Fire and work out from there... Z, understandably, just wants to keep killing Russians to make them pay for what they've done while gaining ground to have more to bargain with at the eventual peace talks...
Z doesn't seem to grasp that the US is the 8,000 pound gorilla 🦍 in this equation and pissing us off could result in his supply line being shut down to a trickle (to a large degree)...
I can see both sides of it... Z doesn't trust Putin for very good reasons and is continuing to push for more security concessions...
We don't seem to appreciate (like) his complete lack of awareness of his circumstances and his seemingly wanting to continue to renegotiate a deal right up to the point of signing it...