It's not about making the engine, anyone can make an engine.
Look some random guy on YouTube managed to make a DIY jet engine:
It's about making an engine that can withstand very high temperatures alongside long service life components. The engine has to work for thousands of hours, in unfavourable conditions, just like a clock, tick tock.
I find it incredibly delusional that people here think TAI can develop a 5th gen engine akin to F119 or F135.
F119 cost $3 billion dollars to develop ($1.36 billion in 1991 dollars), F135 (engine of the F35) cost $7.5 billion, Pratt and Whitney have the human capital and infrastructure to develop these engines at these prices.
Turkey neither has the brain capital, experience, or infrastructure to build an engine like this, even if it does, it would take at LEAST 15-20 years, and could cost $10B-$30B if we include necessary infrastructure that needs to be built - even then it would be below average.
At this point Rolls Royce is a must, RR knows they have leverage, because Turkey has no other engine choices for TF-X. They will NOT give IP rights under any circumstance, the government must understand, but they won't, until it gets very desperate. They should make a deal where RR builds infrastructure in Turkey to manufacture these engines, and provides necessary know-how to Turkish engineers at TAI. This deal could cost Turkey up to $10 billion, but it has to be done. Then we can talk indigenous engines.