On a similar vein, the proliferation of Rafale in the Middle East. UAE will operate 80 F4 variants. Egypt, Qatar already operates them.I don’t think that the issue with S400 is so much that it is overhyped than that it has been played around with by the PLA for a couple of years by now. Same with the Sukhois that make up the backbone of the IAF — China has the most advanced variant (if we discount J-16) in the form of Su-35. No doubt that such knowledge has been conferred to Pakistan sometime before 2019.
All these countries have bonds that go beyond religion/culture. Military cooperation has been there (Arab-Israel conflict and wider Middle East tension times).