RAM coating is in the bag. If you don't believe me, you could use the search function above to see for yourself. No need to worry on that front.While they did pave the way with the general design and the concept of "stealth", when it comes to engines they have a mountain of experience. They first developed the F119, with former experience from F100 all the way to 1950's, and then built the F135 from it. And we've seen the news of the F-35 crashing, having a myriad of minor and some major kinks to iron out over the years in service. We're going to do it cheaper, with no prior experience or research, than the ones developing supersonic thrust systems, for the better part of the century..? Also the RAM coating is still one major problem we have to consider, China, with all its students studying at MIT and the likes, and having access to many classified US industry data through various means, still is yet to develop one on the same level as its adversary. We need to think realistically here. My point is that this project simply requires way more budget than it currently is alloted, if we want to come up a peer system on the same level, in the following two decades.
As for the PPP, apart from the engineer salaries and manned labor costs, the materials and research required for the jet, if it's meant to be competent, isn't going to be substantially less than the US counterparts.
As for the F135, the engine of the F35, it is an troubled off-shoot of a reliable F119 core. Had a lotta issues both in development period, and the usage.
That engine is not our yardstick. F119 is. And since the 80's TEI is very intimately involved with the predecessor of that engine, the F110.
They can rise to the challenge of developing a "T119" , if they are not cash starved or rushed with unrealistic timelines.