Haha, welcome to China.You are undoubtedly in a better position to unravel some of the mystery surrounding Chinese knot production than I am. I have planned to visit China several times but haven't been able to do it yet (other than Hong Kong a couple of times many years ago).
For what it's worth, I don't assume that assembled brushes are necessarily produced in the same place as knots.
Do you know the Chinese names of the Maseto boss and FrankShaving boss?
I'm not sure whether assembled brushes are necessarily produced in the same place ttheas knots or not.
But according to some wetshavers in China, knots of Frank and Maseto are produced on their own.
I can ask the boss of maseto shaving tomorrow. Sorry I dont know the name of them but maybe you can contact maseto on ebay and Frank on aliexpress maybe.
Another welcomed brand is oumo shaving, you can see it on aliexpress.