Can China use its foreign exchange reserves to buy American companies? Like General Motors \ Boeing?

In my personal judgment, even if China wants to buy it (whether the government or state-owned enterprises come forward), the US government will not approve it. On the surface, the United States is very free, and enterprises or assets can be freely transferred and traded. In fact, there are many rules in the dark, and it is difficult to reach a deal without the approval of the US government or Congress. For example, a few years ago, in order to solve the procurement channels of foreign oil, PetroChina wanted to buy an obscure small American oil company with no connection with the United States, and paid a high price of more than 8 billion US dollars for this. The two sides have signed a contract and are waiting for the official approval of the United States. The US Congress refused to approve it on the grounds that it involved US security, which caused PetroChina to lose a lot of liquidated damages. The General Motors or Boeing you are talking about is the core military enterprise of the United States. If you want to buy it, what can the United States do without the approval of the US government at first sight? On the other hand, China has huge foreign exchange reserves. In order to prevent an impact on the US economy, the US government generally does not approve China to buy ordinary real estate. China's foreign exchange reserves can only buy US Treasury bonds, and I'm afraid it won't be allowed to buy shares in enterprises.