having 3 production aircraft does not mean you achieved IOC.The Su-57 has already entered IOC, so the biggest roadblock would be funding for more units and future upgrade programs, not R&D anymore. I suspect that funding is also the bottleneck for their AESA programs since they already have the tech in place in the form of the Zhuk-AE and Byelka systems.
At the current pace, Russia will be buying advanced weaponry from China.
By the second half of this decade, China will be actively promoting FC-31 and unmanned UCAV to export customers. As a top tier ally, Pakistan will have access to certain platforms not available to other countries.Let's not kid ourselves, it'll be years and years before the PAF could ever plan to import 5th-gen fighters and UCAVs from China, and even when that time comes the only options available to them would be the FC-31 and CH-7, respectively. Not that they're lackluster systems, of course.