I just now realized how weirdly one dimensional it is to have Yamaoka always react with such negativity to whatever Kaibara presents - he's super into new food exhibits otherwise, so even if the point is supposed to be that he's resentful, it would make still more sense for him to react like Kyoguko or Dan to the idea of five emperor hot pots
This is a great observation, cause what you've picked up on is the same thing Kurita has noticed in Yamaoka.
For a few volumes now, Kurita has been getting less and less sure of Yamaoka's position. She's starting to question if Yamaoka's claims are entirely true, and that maybe his telling of what happened is too one-sided. This comes largely from her interactions with Kaibara and the people around him, and how many people seem to respect Kaibara as a person, not just a chef.
Kurita and Yamaoka are now on different paths. Yamaoka is on a quest to defeat his father, while Kurita is on a quest to discover the truth at the heart of the matter. Personally, I like this development, as it gives Kurita more agency as a character and prevents her from being just Yamaoka's lapdog.