I just might have realized something about Corruption. It has no personality, etc., but it isn’t stupid. It isn’t actually mindless, which is why in Dead Apple, Chuuya went and punched Dazai while in Corruption. He’s not afraid of using it and despite fanon, there’s actually no indication that Chuuya worries about Corruption destroying those who are on his side. Unless there’s something in the manga I haven’t read yet or heard about.
I’m also of the opinion that Dazai can’t actually nullify Arahabaki. He can nullify Chuuya’s access to it because Chuuya is human and Arahabaki is his ability. Lovecraft isn’t a separate human with his other self as his ability. Lovecraft is just Lovecraft with two different forms.