Wow I didn’t realize that Signal is run on Amazon’s servers and that they contract with the CIA. This article has some interesting points to mitigate the privacy concerns of this real popular service: https://simplifiedprivacy.com/signal-messenger-guide-to-avoid-privacy-mistakes/
They did though. Individuals who are on the contact lists of on on individual can get investigated
The contact list built into your phone? Because that isn’t encrypted of course they would get it
Last time I checked signal had phone numbers in there servers.