Not good enough at translating to add this as notes but here’s my understanding of it
Itadori: Hey, it seems today's date February 22nd is a pun for Cat Day. Looks like a lot of girls wore cat ears and stuff.
[Checking social media]
Megumi: I'm a dog person.
[Checking the mission]
Itadori: Huh?*
Itadori: Cat ears are cute, aren't they~
Megumi: Of course you'd be into that stuff.
Itadori: Um, maybe I'd like it if a girl wearing cat ears suddenly snuggled up to me
Choso & Todo: We heard what you said
Itadori: Please don’t eavesdrop.
Itadori: Is this hell?
*Source: I made it up. No goddamn clue what this actually says.
February 22nd is "nigatsu nijuuni nichi". I guess since "ni/に" is part of "nya/にゃ", that means it's Cat Day