I suspect the reason they didn't take it is more of internal politics, the current government is synonymous with war and growing more and more unpopular as fatigue and stalemate sets in. They don't understand what drives US foreign policy; The US keeps telling Ukraine to avoid striking at Russia itself, and moderating the flow of equipment so Ukraine never gets too successful.

The United States doesn't want Ukraine to lose but they really really don't want Russia to lose either, because that would cause instability (and god knows what could happen when the government of a nuclear superpower collapses). Like, when prigozhin was doing his thunder run to Moscow, they specifically told Ukraine not to rock the boat, even though that's when Russia was at its most vulnerable with its command structure in total disarray/panic.

In general I feel like they just want the Ukraine conflict to simmer down already so they can focus on China (and also now that it's about to erupt, on the middle east).