I have read it. The entire trust hinges on several critical points, such as trusting secure boot.

You remember when the NSA injected itself in TLS termination at all major cloud providers? You remember when several giant automotive corporations built elaborate detection of testing scenarios to fake emissions? You remember room 641A?

I have no real way to tell if this is security Theater or meaningful protection. None of us has,

That's "because they said so" but with more words. Sorry, but a pretty blog post is not proof enough.