There is no amount of nuclear capability that can stop a party you are major threat to from attacking you. See Hamas attacking Israel. Of course Iran will still enrich uranium because they are an excellent negotition leverage.

I think if Washington and Mar-a-Lago got nuked it might stop attacks?

Trump has already tried to use the US' nuclear arsenal, which (according to accounts) caused the Chief of Staff to evict him from the situation room. I don't think nuking US soil (however dirty it already is) will tip the scales in Iran's favour.