When China actually exports weapons, it adheres to its own laws. (Regulations on Export Control of Missiles and Related Items and Technologies)
The law does not specify detailed technical parameters. Actual technical parameter limitations are determined separately by the relevant agencies. Currently, the export control list of the Chinese Ministry of Commerce serves as the standard. You can check the details yourself.
In simpler terms:
China doesn't want to sell certain weapons, so it uses the MTCR (Missile Technology Control Regime) as an excuse. If China really wanted to sell them, it would have countless ways to circumvent these restrictions.