"Whereas a year into a major war a kid in his/her basement can release something that is functionally the end of the human species."

How?

If a a virus is so deadly, everything it touches dies soon, it would not spread quickly but die out. If it is very contagious .. but very, very slow incubation time, so it infects the whole world, before becoming a deadly disease ... then I would say it is far beyond the possibility of a basement workshop to remotely design anything like this. I doubt the professional state labs can create something to wipe out humanity. Dramatically disturb? For sure. Covid was not really deadly in comparison, but already problematic.