I mention in the article that malware could potentially access Signal messages. This is an area where I don't know a lot of specifics, but one thing did pop up recently that I thought was interesting.
NYT and 404Media have reported on new tools purchased by DHS. From NYT:
"One of the tools, which was built by Paragon, an Israeli technology company, lets people take control of phones or remotely hack into them to read messages or track locations."
https://www.nytimes.com/2026/01/30/technology/tech-ice-facial-recognition-palantir.html
Would this include Signal messages? Is this actually in use and working as described? I don't know, but it demonstrates that there are more exotic threats to mobile device privacy.