While SMIC, the largest foundry in China, does have 7nm, the vast majority of Ascend 910B and 910C are made with TSMC’s 7nm. In fact, the US Government, TechInsights, and others have acquired Ascend 910B and 910C and every single one used TSMC dies. Huawei was able to circumvent the sanctions on them against TSMC by purchasing ~$500 million of 7nm wafers through another company, Sophgo.
Goes to show that SMIC's 7nm node is likely somewhat overhyped and may not really be fully viable commercially.