Qatar is interested in the JF-17B, the two-seat version

[Ghessan]

Their foreign policy does not align with their neighboring Gulf states. Saudi/UAE and the others essentially declared an economic and political war on Qatar for several years which left the country isolated in the region, with only a narrow air channel to Iran being it's geographic outlet to the world. https://theintercept.com/2017/11/09/uae-qatar-oitaba-rowland-banque-havilland-world-cup/

News like this one are a way of ensuring political support for Qatar so that in any future case of GCC isolation it is not left alone. It was a close call this time and the worsened relations between Turkey and Saudi resulted in the former nation investing in Qatar politically and militarily. Even relations with Iran are at an all time low during MBS reign ensuring there were some regional countries ready to defend Qatar from the GCC wrath. It was a close call however and Qatar won't be taking any risks anymore. Purchasing weapons from abroad has just as much to do with militarily strength as it does with purchasing political influence abroad and thereby countering hostile foreign influence.

above you said is about geo-politics. but the matter is this buying spree. with such variety of fighter planes and they won't need them in big quantity being small country, maintenance nightmare, pilot training and what not.
they can easily go with two types of fighters.
it does not bring the logic if they are rich they can do what ever they want or is it like parking a lamborghini. aston martin, bugatti in your garage.