American companies are Private companies
Whereas Chinese Military Industrial Complex is directly governed by the Chinese Govt
And US companies aren't guided or governed by the US military? In the US they call this R&D expenditure rather then state control. You still have programs initiated by the US military, funded partially by them and overseen by the US military, but also by the individual companies and the work governed by a mix of both government and private ownership.
Or lets look at it like this. Lockheed is a well known company right? Surely you know the name. You're also likely to know the name of Sikorsky. Maybe you aren't aware that Sikorsky is a Lockheed subsidiary, an with its own independence designs and oversight, but a part of Lockheed.
Chinese companies function as their Soviet counterparts do. State controlled, but given independence over their resources and design. They are individual design companies. Central control.
While both Chengdu and Shenyang are subsidiaries of AVIC, they are independent design bureaus with their own resources, control and projects. Ultimately they report to AVIC, but this does not mean they aren't responsible for their own designs.
Relating this to Lockheed and Boeing, both are independent companies occasionally acting on request by the US military but without formal contracts. Don't think that precludes them from sharing proprietary info with one another, as programs like this or their joint venture the ULA and a joint Boeing-Lockheed submission to the tender that birthed the B-21 show.
Shenyang and Chengdu are independent design bureaus, both with their own designs and projects and funding. Do they collaborate? I doubt you really know. But mistaking the two for one another reflects rather poorly.
Don't you have something else to do other then bother me? Go do it.