What about Ukraine is in our national interest?
Stability in Africa. Ukraine accounts for 10%-12% of the worlds' grain exports, and a lot of that goes to feed Africa. We do not need any more instability there than there already is, (thanks in part to Russian "mercenaries").
https://www.usip.org/publications/2024/04/why-africas-critical-minerals-are-key-us-national-security