Competing ideologies are not a necessary factor in defining a struggle's existential character.There is zero resemblance between USSR-US struggle and Iranian-Israeli spat in the region. The US and Soviets had two competing dominant, global ideologies they were struggling for while Iran-Israel spat is about competing interests.
A state can just as well conceive its interest as residing in another state's removal from the political map. To give you an example, during the recent war in eastern Ukraine, authorities in Kiev sought to eliminate the three Republics which proclaimed their independence there. No globally scaled ideologies were involved.
Now this being said, the Iran-Isra"el" conflict pretty much sees two ideologies confronting each other, and two ideologies with universalist dimensions at that. As far as zionism is concerned, I'd advise to research the concept of Jewish universalism and how it is reflected in the policies of both Tel Aviv and international zionist lobbies. It is no coincidence that zionist elites occupy leading positions in various countries, particularly in the powerful western block. The connections between zionism, Isra"el", freemasonry and messianist globalism, with their ambitions to create a unified one-world regime concommittant with the building of the third temple in Al-Quds, should also not be overlooked.
As for Islamic Iran, the Iranian constitution requires the government to support the disinherited (mustaz'afin) all over the planet. Likewise, Shia Muslim eschathology and belief in the Mahdi shapes Iranian policy making to a non negligible extent.
These ideological, religious and in certain cases even mystical dimensions are all too often obfuscated by analysts. Yet they are very real.
I just did. I will only add, that since Isra"el"'s enmity towards Libya, Sudan, Iraq, Somalia and Syria proved to be very existential indeed, since all these nations ended up being subjected to war, destruction and balkanization as per zionist injunctions (refer to the Lewis-Yinon plan, among other clues), there is little doubt that Iran will be treated in the same manner should the zionists ever be given the chance.It's true, there is no existential struggle between Iran and Israel. You are more than welcome to argue otherwise.