I low-key feel like there should be a distinction between cucking and love polycule collapse
Yeah I was thinking that Yuri and Fuyuki clearly don't count as cucker candidates? They've been around for a while and their relationship with Yuu is good, if she gets with either of them that's just a regular romance.
Really she should either be waiting until the last second to find a cucker or finding one to establish a hostile relationship with.
"We all liked her and assumed she would choose one of us but instead she got with this guy who showed up out of nowhere/this guy we all hate."