There's zero chance they can make a brand new, high output jet engine in one year, when zero of the market leaders want their business.
Are they going to build the engines themselves? Ask China how well that works even when have all the original engineering documentation.
Building a jet engine is not a technical or knowledge or willpower or anything like that challenge. It is a pure engineering challenge. It's about building and iterating new engines hundreds of times until you've made enough iterations that things stop melting in corner cases. It's about finding out, the hard way, every single way your assembly could possibly fail, melt, explode, wear too fast, or otherwise fail.
Understand that making modern engines often requires significant innovation in non-destructive testing to ensure the actual parts you are buying/making are up to spec.
Understand that Russia has a portion of decades of experience building, designing, and INNOVATING in jet engines and still struggles to build modern jet engines.
Understand that China struggles to produce economical modern jet engines despite massive funding, huge incentive, and literal national security concerns. The C19 jetliner currently uses an American engine.
Empirically, building modern jet engines seems HARDER than building modern rocket engines! It seems to require maintaining literal decades of raw engineering experience and patience, and now scale all that effort to a company that in 9 years has been told by all existing engine manufacturers "Nope, we won't make a profit on this plan", and has instead spent their time building a single demo plane that does not demonstrate any experience in building engines.
> zero chance they can make a brand new, high output jet engine in one year
Not one year. "produced by EOY '25" means they're almost certainly already very far along in the development process. There's no way they'd have a target date that early if they hadn't even started yet.
- Symphony engine being produced by EOY '25
- 3 years to have first full size Overture roll off the line
- About 4 years to have it in the air for first time.