I haven't seen Seasons 2 and 3 yet but I've read summaries.

Do they have ANY of Saitama one-shotting enemies? From the sound of things it's one main antagonist for BOTH seasons, Garou, who survives. As opposed to three arc antagonists of Season 1, the only one to not be killed by Saitama is Professor Genus who had his strongest monster, Carnage Kabuto, serve as final boss in his place.

Maybe I misread, but from the sound of things it departs from the whole premise of the show. I know he's pretty bored with it but still.