I’m pretty sure Crimea will be ceded to Russia in the eventual treaty in exchange for NATO-like security guarantees for the rest of Ukraine, as unfair as it is. With how many Russians there are now, the enmity that will exist for a generation, and Sevastopol being a Russian base for a lot longer, I don’t think US diplomats see any realistic way they can materially support a retake Crimea that will lead to a stable situation. However that’s up to the Ukrainian people, which currently majority don’t want to cede it.