When King Salman had that early grand meeting with President Trump, they inaugurated a new coalition planning and coordination center. Another US Israeli center was established a few months later.
Also a key player in the Riyadh meeting, was the Egyptian President - commander of the largest Sunni Arab Army. Egypt could play a role in countering Iran in Yemen, or Syria (where Egyptian troops could be acceptable to both Syrian and Russian Governments, based on long relations).
What were they planning?
I'd rather see Al-Sisi's Egypt as the main power broker representing Sunni Arabs. Unlike Saudi Arabia, Egypt's de facto military dictatorship is secular to the core and not beholden to radical clerics. Unfortunately, Egypt doesn't have the oil wealth necessary to be the region's main power broker, although as you note Egypt has the Arab world's largest standing army.
——Another US Israeli center was established a few months later——
I think that the level of colonels, there has been GCC/Israeli military alliance for several years. That is now at the working level of the Generals on a day to day basis. Where? God only knows. It’s very very secret.
Recall if you will, that years ago, Saudi Arabia allowed Israeli over flights to attack Iran. That never happened but there was a cooperative effort.
Regarding Egypt...... you are of course absolutely correct.
Here’s the deal.
Iran has attacked Israel with missiles from Syria. Direct Iranian assault
Iran is now attacking Israel from Gaza via Hamas as a surrogate
Iran has attacked Riyadh with missiles from Yemen with the Houthis as transparent surrogates.
It is past time for Israel and Saudi Arabia to directly attck the Iranian mainland.
I don’t think Iran has the military wherewithall to come out ahead