From the very beginning we knew that Pakistan will definitely choose J31 over AZM. even Pakistan is not likely to buy AZM, its just a smokescreen for military intelligence.
1, Logistical advantages. Pakistan already has many Chinese fighters and the continued use of Chinese 5G fighters will drastically reduce logistical pressures. Turkish fighters will require a whole new logistical programme.
2, 5G fighters have been in service in China for over a decade. The number of 5G fighters China has is second only to the United States. And Turkey has zero experience.
3, The J31 is a mature platform that China completed validation of many years ago. China has even been developing a naval version of the J35. and it is still unknown if the TFX will be successfully developed. Any investment in TFX could be wasted.
4, Weapons. The Chinese fighters use a wide range of munitions that are not only complete but also advanced, and they have long been tested by the Pakistan Air Force. On the other hand, the Turkish fighter jets get their ammunition from different European and American countries, and it cannot guarantee that it will not be cut off from its supply. This will bring great diplomatic pressure.
5, Engine. China's WS15 engine has been in service for many years, and the WS19 engine has matured. Turkey still hasn't solved the engine problem until now. Even if Turkey eventually finds the engine, it is likely to be sanctioned by Europe and the United States at any time, cutting off the supply of the engine.
6, China is able to produce every subsystem and piece of equipment on a fighter jet, so Chinese fighters usually have a big price advantage. Turkey, on the other hand, relies heavily on technology from other countries and the price is likely to be high.