The US administration has given several contradictory claims as to what the strategic goals of the war are supposed to be.

The problem with the claim of nuclear weapons program is that the dominant assessment of the intelligence communities is that Iran didn't have a nuclear weapons program at all. Khamenei the elder was known to be against having a nuclear weapons program, and the US's achievement is to replace him with his son... who is known to be in the pro-nuclear weapons program. Considering that the nuclear enrichment centers were targeted in last year's strikes, it's not even clear that the strikes this year have had a meaningful effect in even a temporary delay in enrichment progress.

At this point, I suspect that Trump never had any strategic war aims in the first place, but was instead motivated by an operational aim (regime change in Iran, à la the Venezuela operation), and has been flailing about since then because the administration simply doesn't have anyone with the capacity to actually understand the strategic reality of the situation and is substituting operational and tactical goals for strategic ones.