you can use freefrom app, and use content language filter on plaza, add 中文 for it, then you can see many chinese language users there.
chinese users normally can not connect to popular relays such as relay.damus.io/relay.nostr.band and so on, they all banned by GFW.
Deploying relays in mainland China is not a good idea because Chinese users will not trust relays running in mainland China and are worried that they are phishing relays deployed by the government. Therefore, generally Chinese users will use VPNs to connect to popular relays or themselves Deploy relays outside mainland China. There are currently relatively few relays deployed. Some Chinese users in Taiwan and Japan have deployed relay servers, and some users have deployed proxy forwarding type relays through the bostr project (for example: https://bostr.online/ ) to solve the problem of GFW blocking popular relays.