I will not offer an assessment of the KAAN fighter jet (doing so would merely spark a great deal of pointless debate).
The J-35 series of fighter jets is fundamentally designed around a concept of system warfare.
Simply put, this means it relies heavily on a national-level air combat command and support system. Many of its operational capabilities do not reside within the aircraft itself, but are instead derived from external support systems. Furthermore, certain capabilities inherent to the aircraft function as integral nodes within this broader operational network.
Should the PAF acquire the FC-31/J-35, these specific functionalities will undergo modification.
Specifically, certain systems originally intended for external system-level support will be integrated directly into the FC-31/J-35 airframe, while certain capabilities originally designed to function as robust network nodes will be removed. (The specific scope of revisions is entirely based on PAF's requirements.)
Of course, were the PAF able to expend substantial financial resources within a relatively short timeframe to establish a comprehensive national air combat command and support system of its own, such modifications might prove unnecessary. However, this scenario appears to be rather unrealistic.