I didn't find it particularly funny either, and I would say that it was even less humorous in Japanese. I haven't seen enough manzai to know whether it's supposed to be good or not.
I've never really "gotten" manzai comedy. Like I get it in the sense that I understand what it's going for, and I like both wordplay comedy and slapstick. I just don't ever think I've found a manzai routine that I've seen translated into English that I think is funny. And it's not even that the straight man/joker comedy duo concept doesn't translate because that was a big deal like 50-80 years ago in Vaudeville and there are classic comedy duos from then that I have heard and do think are funny (Abbot & Costello, Burns & Allen, The Smothers Brothers, etc). This just doesn't work because it feels like the standard manzai duo is:
boke: says something particularly dumb that's not even clever, it's just baffling.
tsukkomi: calls the other person an idiot (again not in a clever way, just straight up) and might smack them
and that's it. Maybe it's because manga writers can't do that sort of comedy easily enough otherwise they would actually employ it as more than a random gag in their manga, but after so many times where the punchline seems like it's just "you dumbass!" ~whack~ it just has no effect on me.