No better diversion than another another war if just because it enables to proclaim martial law (= totalitarian police state with FEMA camps for dissidents, political opponents etc.).

As Iran no longer trades oil in US $, it is a major target, contrary to North Korea which boasts having nukes but has no oil (so is of no importance till the next need for diversion from economic collapse arrives).

Apart from that, it might be obvious that Iran would have nothing to gain from assassinating a Saudi ambassador but to the contrary, has a lot to lose by executing such a foolish scenario that woul serve as an excuse for the Zionist bloc to liberate the oil.