If they were to go with that path, I feel like they could use DoL's example of Attractiveness and Allure, though 'localised' for the purposes of CoT. In DoL, because the MC has some sort of 'mysterious charm', regardless of how they actually look like, attract attention to them whether they wanted this or not, both the good sort and bad (mostly the bad, really; Attractiveness and Allure, the two sides of the same coin, exists mostly as another sort of passive difficulty increase over time).
That said, DoL does have (and is primarily about) non-consentual content aimed primarily at the MC, so the Attractiveness/Allure thing was designed with that in mind. Given the setting of Cot, it doesn't make as much sense for FKU to be a 'campus of rape' (unless as a 'hidden hard mode'?), so perhaps the only way about it is to break them down into various numerical stats - 'Attractiveness' stats based on the NPC's clothing style likes and dislikes, and 'Allure' stats based on the NPC's turn-ons and turn-offs. Maybe allow this for the MC as well so that if you want to 'RP' based on these stats, you could (especially if you can later on influence NPCs into wearing certain clothing styles).
As for how 'Attractiveness' and 'Allure' would work in terms of CoT, for Attractiveness, it'd instead make it how much more likely the NPC reacts positively to the MC, or how more often they may approach the MC to talk or hang out. Though simplistic, perhaps this could also be used as a way to make non-unique NPCs that seem to perpetually dislike you be more friendly to you, if you decide to dress up in a style they prefer, allowing one to repair relationships easier without needing to RNG talk until you have the 'they show a bit of interest' result. As for Allure, they instead make it how much more likely you'd get NPCs giving you lewd looks (e.g. for female MCs, catching NPCs looking down your exposed cleavage or up your skirt), maybe even down to some sexual harassment or even rumours (e.g. NPCs trying to cop a feel or the MC starts popping up on a 'top 10 hottest people want to fuck' list that occasionally pops up on social media). Otherwise it also increases the likelihood the MC gets approached for dates, even if the NPC is already in a relationship (unless NPC is chaste).