lsb_release -a; # tested with
Distributor ID:	Debian
Description:	Debian GNU/Linux 11 (bullseye)
Release:	11
Codename:	bullseye

su - root
sha512sum 7e977fde8a2fc370d7df24f761e75eced308ea17037113db877bd799abec4a3a9b6324fcbfda2d2a67d63fbe23b822abbd36ab0f9af4fc5c352df04a97dbe550

# needs to be dpkg installed manually

# install requirements
apt update && apt upgrade
apt install psmisc software-properties-common libvpx6 libqt5opengl5 libqt5x11extras5 libsdl1.2debian linux-headers-amd64 linux-headers-$(uname -r) gcc make libqt5printsupport5

# install virtualbox
dpkg -i virtualbox-6.1_6.1.32-149290~Debian~bullseye_amd64.deb

# if an error occurs like
You might want to run 'apt --fix-broken install' to correct these.                                                                                                                                                                
The following packages have unmet dependencies:                                                                                                                                                                                   
 virtualbox-6.1 : Depends: libqt5printsupport5 (>= 5.0.2) but it is not going to be installed                                                                                                                                     
                  Recommends: libsdl-ttf2.0-0 but it is not going to be installed                                                                                                                                                 
                  Recommends: linux-image but it is not installable                                                                                                                                                               
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).                                                                                                                                                                                              

# apt magic fixes it
apt -f install
dpkg -i virtualbox-6.1_6.1.32-149290~Debian~bullseye_amd64.deb

# if installation was success
# another go of might be needed
/sbin/vboxconfig Stopping VirtualBox services. Starting VirtualBox services. Building VirtualBox kernel modules.


it might be usefull to run this on a separate console to monitor all logs

linux monitor all logs in real time 😀 – follow all – show changes to log files under /var/log