When that happens, the US will just ban Chinese aircraft from US airspace and impose economic sanctions on the Chinese aircraft industry under the pretext of IP theft and/or National Security<tm>.
That is the Washington solution for Huawei, TikTok, and Tecent after all.
I don't think they're more than 2 or 3 years from that.
They can do airframes but they are still far behind in avionics and engines. If the C919 ships in 2-3 years at all, it will be with CFM LEAP engines and American avionics. The problem for China is you cannot cut quality in aviation; there is no such thing as an affordable, lower quality product as there is in consumer products. We’re talking ca. 2030 for a competitive Chinese airliner.
China has been capable of creating quality products in other areas, for example their national high speed train, satellite, and electric car industries. Avionics take time, that is true, but I would say that in 3 years they will have the necessary technology.
The C919 is supposed to have its first deliveries next year.
Counterpoint: Sukhoi Superjet had its "deliveries" years ago, and now several of them have crashed and nobody wants to buy or fly them anymore. And that _Sukhoi_ - those guys have been designing and building planes for 81 years. Just not passenger ones. On paper, the plane is "competitive". Doesn't mean jack squat.