Agreed - most people would basically like to see an end to the war, which is what is broadly envisioned by a "negotiated end to the war".

But I'd question your assumption that Americans aren't willing to invest what it would take to win the war (depending on what a victory entails) and instead I'd suggest that this assumption needs a bit more research. I for one am very happy to see our tax dollars be used to support Ukraine, primarily because I think it's an investment in preventing a more expensive war in the future. It's unfortunate because we are basically just incurring a cost we didn't want to incur, but at the end of the day this is just the hand we're dealt with.