Last I checked, it tied every single communication to a pair of phone numbers.
i know "whatsapp admins" who have been made to report to police stations because they operate "whatsapp news channels". there they are made to submit their phone and wait outside. then the phone is returned. i have suspected, for like past 3 years that pegasus style malware would have been installed during that time.
now, a lot of these issues and problems can be reduced/prevented if you were not required to mandatory link your mobile number. if they know me by a handle, rather than a phone, it would be a little bit harder to do mass surveillance and bullying.
this was last yearand it continues. i have taught people to use launchers on android like evie that lets you hide apps. that saves you a lot of roadside quick grief. same for using password protected "gallery" like simple gallery to keep stuff behind a password. a thorough check will defeat all this but saves you in the field as you can be randomly picked.
whatsapp/signal/telegram as i said is more difficult, even clubhouse because since your phone is already public, the police do join groups, public or private using any means, lets say by surveillance, by getting access from company side or "borrowing" a phone from a member. then they just get a list of names and go knocking on doors. if the number was not there, it would have been much more difficult.
As a simple example, they could easily log whenever account xyz connects to do a token exchange for using sealed sender. Asking that of Signal won't be something I'd expect a judge would consider excessive if there is a legitimate reason.