The PRC intentionally deflated private companies that it felt needed deflation (e.g. construction sector) so it’s probably unsurprising that the private sector decreased in size.
China doesn’t need continual FDI. They need FDI to speedrun manufacturing and technology development instead of having to do all the R&D needed to get it. This implies that the need for FDI will decrease over time as China learns how to build the things it previously couldn’t. The PRC does not seem interested in making money for foreign investors other than when they want to get their know-how.