However as we are migrating to debian 11 bullseye, there is no repository targeted to that. Is there any other repository or will buster one be fine as of now? Or will buster repository be available shortly?
Debian-based Linux distributions
Add the following line to your /etc/apt/sources.list. According to your distribution, replace '<mydist>' with 'eoan', 'bionic', 'xenial', 'buster', 'stretch', or 'jessie' (older versions of VirtualBox supported different distributions):
deb [arch=amd64] https://download.virtualbox.org/virtualbox/debian <mydist> contrib
Thanks