It will probably cause a slowdown in Chinese GDP growth to survive the US decoupling onslaught. It will ofcourse hurt US too and will certainly be beneficial for China in the long run, since they will become self sufficient. But it will be extremely painful and China will have to sacrifice their GDP growth for at least 10 years and invest all that money into self-sufficiency. Otherwise they are doomed.
I don't see this causing much overall slowdown in China.
China imports 70% of its semiconductor needs.
If those imports are blocked, then there is no option but to buy whatever chips are produced from Chinese fabs.