virtualbox.org

Virtualbox is still not installable under Ubuntu Groovy (20.10) thanks to this bug: https://www.virtualbox.org/ticket/19897 and there still seems to be no groovy packages available: http://download.virtualbox.org/virtualbox/debian/dists/

Does anybody know if and when groovy packages including correct python(3) support will be available?

Nobody here would know. The forum is supported by volunteer fellow Virtualbox users, and the developers never reveal plans or timelines. You'll need to keep monitoring the Downloads page until the supported download appears.