Also the sanctions are international, they hit Iran’s economy, but the regime could get rid of them at any time. It’s just that war and nuclear weapons are more important to them.

They had already agreed to not pursue nuclear weapons, and let international observers in to verify, in the talks that ended apruptly when the US and Israel started bombing them.
And before that, there had already been a deal in place, which the US unilaterally pulled out of.