There are big wishes for Signal to adopt the perfectly working Flatpak.
This will make Signal show up in the verified subsection of Flathub, it will improve trust, allow a central place for bug reports and support and ease maintenance.
Flatpak works on pretty much all Distros, including the ones covered by their current “Linux = Ubuntu” .deb repo.
To make a good decision, we need to have some statistics about who uses which package.
The concerns about AWS servers are around metadata. If metadata were not a concern, why not just use Whatsapp? They use the Signal protocol so messages are end-to-end encrypted by default, and most people already have it or are willing to download it as compared to Signal.
Signal also encrypts your metadata. (And notably, WhatsApp does not.)