It is a privately held company with no plans for IPO and no dealings with venture capitalists

According to https://pitchbook.com/profiles/company/64901-80, there's over 100 investors in Epic, and of course there is Tencent holding a 40% share.
But those investors are not much of an issue either, because you forgot one important point in your list: Epic is swimming in money (and Unreal is just a side business for them).