Do you want to learn how to produce a Lada when you are geared up to produce and being taught how to produce a Mercedes S class ?What's wrong with getting assistance from Ukraine? Manufacturing capability is one thing, what Swiss watchmakers call "Savoir-Faire" (know-how) is another. Know-how is accumulated, sometimes over centuries; capability can be transferred. Ukrainians have a long history of designing and manufacturing aviation engines and they can probably teach us a few things that GE isn't so eager to share. I think it's a good idea.
Our only deficiency is the lack of an eco system to produce a complete jet engine. You need a long line of manufacturers/subcontractors that can produce every bit of small accessories and parts that are too costly for TEI to produce in house.
Unfortunately we don’t have it. But the Ukrainians do.
Manufacturing of Ukranian engines will not teach us anything. It will not teach TEI how to produce a Blisk Fan or a combustion chamber that can be produced by additive technologies. Soviet era technology is few decades behind the tech TEI is using. TEI will never get their hands on technology on how to integrate CMC parts in to an engine by producing Ukrainian engines.
Since the collapse of Soviets, Ukrainian Motor Sich or Ivchenko Progress have not successfully produced/developed a new engine. They still produce what they were producing in Soviet Era.