Consider all the work I listed above. Imagine you actually did it. Great. But ... you're using WhatsApp to communicate with someone else. Did they do the same work? No? What if their device received a different binary to yours?

You can't even solve this with clever auditing frameworks because then you're just shifting the trust to whoever writes and distributes the auditing tools.

That's why it's so important to understand that you cannot solve political problems with cryptography. At most, you can reconfigure the set of people you need to trust (hopefully by making it smaller). But if those people can be forced to act by a political entity, then no crypto will save you.