The Brotherhood is basically just moderate ISIS. They’re Pan Islamists who want a worldwide caliphate based on Sharia, the difference with ISIS is that their practice of Islam is more mainstream and they’re more ambivalent on the use of political violence

But that doesn’t matter too much, what does matter is the worldwide caliphate part. In the MB’s ideal world, they’d depose the Gulf Monarchies to add them to the Islamic superstate. This is why Saudis and UAE view them as an existential threat