i am also curious to know if any of the mentioned factories oems for any specific western brands.
Even if they did, it wouldn't mean that you necessarily get the same frames, quality control processes or carbon layups. Buying a Chinese frame is not the same as buying a western frame but without the logos - there's a lot of things you can't see (and may not ever have visibility of).
Any of the common vendors here will likely be fine - e.g. LightCarbon, Velobuild, XMCarbonSpeed, TanTan, SPCycle, etc. - but none of this guarantees that you personally will get a good frame.