There's two types of Mori Calliope and I used all 3 braincells I dedicate to her to seperate the two and call them Mori and Calli.
Mori is the one that isn't enjoying the game she is playing or what she is currently doing. She "tries" to be natural but she uses a specific tone that she thinks is fooling people but isn't fooling anyone. This is also the Mori that hates everything about idols. She puts on her fake accent and tries to subtly mock it. Since she can't fool anyone with her acting, it brings a certain tone to collabs and ruins the mood more often than not. She feels like a retail employee on a promotional video for the store they work at.
Calli, on the other hand, is actually enjoying what she's currently doing. Since she's actually happy, she talks naturally and talks with chat in a positive manner. If it's a collab, she'll be natural and the collab will be fun. She's an actual streamer.
The issue is if you watch her, you mainly get Calli. If you don't, you pretty much only see Mori. I generally don't watch her so I see Mori more often than not and Mori is cringey as fuck.