You're being too negative about this.
Yeah, she's graduating, we're all in tears.

But we shouldn't beat ourselves up over it, we knew that eventually, they'd leave for one reason or the other.

She definitely didn't leave on a sour note, otherwise she would not be allowed to still do collab streams post announcement. Other members even talked about it and have also tried to convince her not to leave as well (Mio herself talked to Coco personally and di learn what Coco's decision was in doing this).

That's why we need to make the most of it with our lovely Kaichou, maybe she'll never be seen again, but the memories we made, the fun we had with her, it will not be forgotten, it will not become a burning memory.