What Ukraine needs is planes that can carry a weight of standoff bombs and missiles. That ain’t the F-16s metier. I’d want a few squadrons of A-10s. F-16s require antiseptically clean runways due to the underslung air intake. A-10s can operate off dirt roads if necessary.
Some nations in NATO have Migs from the Soviet era.
US could trade F-16s for the more familiar Migs.