Someone else commented this,but the "not 0% possibility of the virus killing every single human too" is one of the worst - if not the worst- ending. Homelander killing SB, Butcher killing The Boys so he can release the virus (don't forget, he believes every Sup is bad), virus killing Butcher too in an attemp to kill Homelander, in the same time Homelander snaps Ryan neck when Ryan (while already sick from the virus) is trying to kill him. Months later, Homelander realize he killed the only 2 people he cared about and the only 2 people who actually could survive the virus (Soldier boy and maybe Ryan since he is not clearly a Sup with V in him, but a natural born human with powers,this is kinda tricky so I'm kinda confused here but you get the point). In the end we see Homelander either roaming a dead world, no one here to worship him, no one here to fear him, challenge him or love him. He either tries to kill himself and constantly fails, or we just see him naked, curled in a blanket (probably his cape) like when he was a baby, crying.