I think an ‘Islamist’ vs ‘secular’ analysis helps to understand the who’s who of the post-Arab Spring Middle East (the inverted commas are to acknowledge that the simple terms cover a great deal of complexity). Counter-intuitively to some, KSA and the UAE have been lined up behind the ‘secular’ parties since a sharp deterioration in relations with Muslim Brotherhood-led Egypt, whose first moves on the regional scene exposed the acute vulnerability of the Gulf monarchies to Islamist-inspired popular dissent. This explains KSA’s rapid switch to support Sisi’s overthrow of Morsi and the societal transformation project being attempted by MBS. Meanwhile the Turkish and Qatari leaderships do not have the same vulnerability; indeed Erdogan rose to power at the head of the moderately Islamist AKP. Both have favoured the Islamist parties in regional conflicts as a convenient way of securing influence. Turkey even sent troops to Qatar at the height of a political spat between the latter and KSA.
Russia? Anti-Islamist (think Chechnya). This makes them uneasy bedfellows with Turkey, but Putin can afford the luxury of a transactional relationship without having to worry about charges of hypocrisy. You can bet your last dollar that the S400s will be on a tight leash to stop them being used against Russian interests.
The UK? Between a rock and a hard place (hence the non-publication of a report into Muslim Brotherhood influence a few years back, and a subsequent ‘argument’ between the Government and Parliament’s Foreign Affairs Committee which is documented
here).