~$ sudo apt-get install aptitude
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 aptitude : Depends: aptitude-common (= 0.8.12-1ubuntu4) but it is not going to be installed
            Depends: libcwidget4 (>= 0.5.18-1) but it is not going to be installed
            Depends: libxapian30 (>= 1.4.14~) but it is not going to be installed
            Recommends: libparse-debianchangelog-perl but it is not going to be installed
 blueman : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
           Depends: gir1.2-ayatanaappindicator3-0.1 but it is not going to be installed
 dbus-user-session : Depends: dbus (>= 1.12.20-1ubuntu3)
 dbus-x11 : Depends: libdbus-1-3 (= 1.12.20-1ubuntu3) but 1.12.16-2ubuntu2.1 is to be installed
 gir1.2-gtk-3.0 : Depends: libgtk-3-0 (>= 3.24.24) but 3.24.20-0ubuntu1 is to be installed
 gnupg : Depends: gpgv (>= 2.2.20-1ubuntu3)
 gpgsm : Depends: libksba8 (>= 1.5.0) but 1.3.5-2 is to be installed
 libpython3-dev : Depends: libpython3.9-dev (>= 3.9.4-0~) but it is not going to be installed
 lz4 : Depends: liblz4-1 (= 1.9.2-2) but 1.9.3-1build1 is to be installed
 onboard : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
           Recommends: gir1.2-ayatanaappindicator3-0.1 but it is not going to be installed
 python3-apt : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-dev : Depends: libpython3-dev (= 3.8.2-0ubuntu2) but 3.9.4-1 is to be installed
 python3-gi : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-gi-cairo : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-markupsafe : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-netifaces : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-pil : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-protobuf : Depends: libprotobuf23 (>= 3.12.4) but it is not installable
                    Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-psutil : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-renderpm : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-reportlab-accel : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-simplejson : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-systemd : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 python3-talloc : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
                  Depends: libpython3.9 (>= 3.9.1) but it is not going to be installed
 python3-uno : Depends: libreoffice-common (>= 1:7.0.0~alpha~) but 1:6.4.7-0ubuntu0.20.04.1 is to be installed
               Depends: libreoffice-core (= 1:7.1.3-0ubuntu0.21.04.1) but 1:6.4.7-0ubuntu0.20.04.1 is to be installed or
                        libreoffice-core-nogui (= 1:7.1.3-0ubuntu0.21.04.1) but it is not going to be installed
               Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
               Depends: python3.9 but it is not going to be installed
               Depends: libpython3.9 (>= 3.9.1) but it is not going to be installed
 python3-venv : Depends: python3.9-venv (>= 3.9.4-0~) but it is not going to be installed
                Depends: python3 (= 3.9.4-1) but 3.8.2-0ubuntu2 is to be installed
                Depends: python3-distutils (>= 3.9.4-0~) but 3.8.5-1~20.04.1 is to be installed
 python3-yaml : Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
 rhythmbox-plugins : Depends: libimobiledevice6 (>= 1.3.0) but 1.2.1~git20191129.9f79242-1build1 is to be installed
                     Depends: librhythmbox-core10 (= 3.4.4-1ubuntu4) but 3.4.4-1ubuntu2 is to be installed
                     Depends: python3 (>= 3.9~) but 3.8.2-0ubuntu2 is to be installed
                     Depends: python3.9 but it is not going to be installed
                     Depends: rhythmbox (= 3.4.4-1ubuntu4) but 3.4.4-1ubuntu2 is to be installed
                     Depends: gir1.2-rb-3.0 (= 3.4.4-1ubuntu4) but 3.4.4-1ubuntu2 is to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).