There isn't really any choice here.
China is the Only one even remotely interested in selling Pakistan a 5th gen jet.
The Americans wont sell the F-22 as it is illegal to do so under US law.
In fact because the US wont give Japan the F-22 they went about developing the ATD-X. Which it will no doubt not sell as well.
The F-35 will be a NATO or US ally staple, meaning giving it to country with so cosy ties to a rival, will just mean loss of tech.
the only Planes that could be sold will be the Chinese or Russian/Indian ones
Since the Latter is out as well, for obvious reasons.
Pakistan has only one source. CHina
You take whatever they offer You.
Super 10 is at best a 4+++ fighter. it is just an upgrade to an existing concept
same goes for the
JX-17 which is not stealth, it as stealth features, no internal weapons bays, nor the ability to super cruise. ( frankly this is the best plane concept for the PAF i have ever heard, you should certainly get it, but it is not 5th gen.)
Since the J-XX project was just a competition between the J-13 and j-14 designs for a stealth fighter. of which the J-14 won.
That leaves you with one choice the J-XX.
Which will no doubt only be given to PAK as an Export version. If the jet is ever offered.