I was pretty sure Yotsuba would be chosen after Itsuki's side in this arc. Allow me to explain:
Every other quint besides Itsuki and Yotsuba had their shortcomings and weaknesses addressed and character arcs finished up until this arc. Some loose ends (like Miku's) here and there, but mostly finished. Itsuki had hers in her own mini arc inside this arc, hence her 3 chapters, but Yotsuba's arc was a fake out. She is still running away from her issues and sources of conflict AND, most importantly, her issues/inner conflict are intrinsically linked with Fuutarou. Itsuki had a foreboding line this chapter, as the future will not be as smooth as we think for the canonical ship. Itsuki is the most aware of the quints about Yotsuba's feelings, and I think she knows that Yotsuba's gilt will be a major hurdle in her relationship with Fuutarou.
Strap on boys, we've reached the endgame now. Yotsuba finally will have to face her demons head on (instead of pussyfooting around), she'll have to overcome the guilt she feels for not living up to the promise she made Fuuts.