

Careful with this!
You need to change the repo priorieties to REALLY low, otherwise your system may downgrade packages and stupid shit like that.
Trust me, I extracted PopOS repos from ubuntu noble based PopOS and installed cosmic apps on debian. It worked, until it started messing up my system.
Use nix, it is way cleaner. On Debian I basically use nix for everything because many packages are missing or outdated.






















The only address book I know is thunderbird any maybe the GNOME or KDE suite (their Personal Information Management (PIM) Suite).
Maybe the small desktops have alternatives.
Thunderbird supports CardDAV for syncronizing contacts too. But it is unencrypted so I wouldnt use it.
Etesync is encrypted.