Even State Department-funded Human Rights Watch admits that authorities combine legal and illegal methods to obtain convictions: https://text.hrw.org/report/2018/01/09/dark-side/secret-origins-evidence-us-criminal-cases
Combining dragnet surveillance with device hacking is intended in the design of both tools. Hence, State Department-funded Signal dupes you into handing over your identity as part of the population-centric mapping. In custody, your phone will be hacked when it is taken away if it’s important.
https://xcancel.com/hannahcrileyy/status/2034273723667161480#m
If the only data surfacable from Signal is the phone number, not the crypto conversation, they didn’t source you on signal and get your number, they got your number through other means and used it to prove you use signal.
They can’t see the conversation to contents to supoena the number to id.