I’m not convinced that Iran has damaged their relationship to the gulf states any more than the US and Israel have damaged theirs. The US has clearly demonstrated that they are willing to use their bases in an allied state to start a war of at least questionable legality that has the entirety predicted outcome of massively damaging the allies economy, possibly for decades to come. All the gulf states will soon re-evaluate their security relationship with the US. On the side, the US has also severely damaged NATO, to the point that NATO states have closed their air space to US planes involved in the war. On top of that, some European states have blocked flights transporting weapons for Israel. Not to mention the fact that Iran and the rest of the world has been demonstrated again that negotiations or agreements with the US do not mean anything. China will look appealing as a guarantor or peace soon to a lot of people.
I believe the long term damage this has caused in immeasurable and the only way to remedy this would be that both Israel and the US find some way to investigate who and why started this war - and possibly prosecuting any war crime that may have occurred.
Also, the EU needs to grow a spine, fast.
But alas, I have no hope of that happening. We’re all worse off for that.