In fact, there are many trainz forums in China with excellent asset quality, but I cannot be sure if you can understand Chinese or register an account...
Moreover, the vast majority of assets on the forum are made for TRS12, while assets for TRS19 or TRS22 are relatively scarce on the forum.
At the same time, the vast majority of creators tend to prefer paid rather than free broadcasting.
Paid assets are usually of good quality.
If you need it, I can provide you with the website of the China Trainz Forum!