No use speculating on that anymore. Was all done from 2010 to 2018 lol. Su-57 may have considerably better RCS compared to clean SH. It may have only comparable RCS, who knows. It's not all just external shaping. It's materials too and the Russians suggest their Su-57 use specialised stealth materials. The SH simply does not have that level of "detail" on everything. The Su-57's main RCS drawback is the exposed fans. Which was the topic of the posts. When I brought up the Su-57 I meant out of visibly definite stealth fighters there's the two Lockmart products and the J-20. The Su-57 seems to have the exposed fan issue (among some others) and the KFX has no internal bays. So if TFX delivers a Lockmart style 5th gen with internal bays, it's already part of that former group.
The TFX's timeline is ahead of AMCA and if we, for sake of this point, negate the KFX and Su-57 (paint, fan, canopy vents, vents, spherical OLS, fuselage tunnel), then Turkey will be the third nation to produce a 5th generation fighter (of the definition implied here). I'm ignoring outsourced components and engine etc. I'm qualifying this as simply their own product as in produced by themselves and supplied for their own airforce.