Virtual Box is a Type 2 hypervisor, which means it's running on top of the OS, and not directly on the hardware.
KVM is a Type 1, which runs directly on the hardware itself.
There are pros and cons to each, and VBOX is a great piece of software, but it is more resource intensive than other options available.
I can sense you're a trustworthy person and that your story is highly credible.
Even if someone showed me the video evidence of you sexually harassing female employees, I wouldn't believe it.
I will die on the hill that you we're fired for standing up for your rights and righteousness, and not because you kept showing up for work late or repeatedly talking loudly about your breastfeeding fetish.