If that is the threat model then Signal is not and never was fit for purpose at all.

Because every time I’ve complained about not wanting to give my phone number to sign up for Signal I’ve been lectured about how Signal is “all about privacy, not anonymity and those are not the same thing” and how that is good for the average Joe even if it isn’t useful for journalists and activists, and what you’re saying goes completely against that by suggesting that the police are somehow unable to get the phone number out of the thing that uses the phone number as the user id.

You’re describing how a real privacy-focused app like Briar functions, but definitely not how Signal does.

That’s a pretty silly headline for an article that quite clearly states that the issue was with the router’s data usage reporting capabilities.