AFAIK, apt-get and most if not all linux package managers only work system wide, and I can't install something just for a specific user.
Not all. Nix and guix allow you to install packages into your own profile as an unprivileged user. Best of all, packages that are installed by multiple users are shared in the Nix store.
Not all. Nix and guix allow you to install packages into your own profile as an unprivileged user. Best of all, packages that are installed by multiple users are shared in the Nix store.