Welcome to Middle East politics. The people who live here are in the same boat with rumours and complex theories about who is in cahootz and what they really want.

In truth, I think the ME is a relatively uncoordinated place. All these different motivations and intesrests exist. Thhe pipeline idea is real-ish, the Qatari support for "extremist Islamists" is too, though Saudis support Islamists too when it lines up. So, it's hard to entirety dismiss or disprove any of these overarching motivation theories. The US and Russia have always proxy-fought in the region, but they never really knew what they wanted there.

My thought is that there is no coherent actor, just a mishmash of interests, ideologies and unpredictable chaos.