Hi, from the forums and my understanding, it is not possible to install Virtual Box on Debian Buster because of decisions made by the Debian team (wikidebian. org/VirtualBox). However, I was able to install Virtual Box following these directions and it worked: vituxcom/how-to-install-virtualbox-on-debian-10/.
Are there any risks (security) etc… that I’m missing or would it be fine to use Virtual Box installed according to those directions?
As your link says, VirtualBox isn’t patching older releases for security problems. This doesn’t fit well with a long-term stable distro. The risk to you is that you unknowingly run software with known but unpatched issues.
Whonix works fine on Debian with KVM/Virtual Machine Manager.