I don't believe it either, at least a demonstrator/prototype should be available by now and it should also work and have a few tests behind it so that the schedule is realistic.
There is absolutely no evidence for this....
Just testing and certifying and troubleshooting both the hardware and the software of the engine is a matter of several years.
The pilot's life depends on it, it has to deliver full performance in both normal and stressful situations on the aircraft, the tests for material fatigue due to heat, cold and pressure alone are simply extremely time-consuming and not a matter of a few months.
And here is the talk of series production aircraft with Turkish engines from 2028, that is simply a lie I ask you .... don't believe every crap that is posted on Twitter.
The Turkish engine will come, but realistically not before 2032-34.
Until I get confirmation from KAAN from the manufacturer TEI, anything else is pure speculation in the realm of fable and a waste of time.