Don’t get the Sage path hate. She’s very much in character - remember, this is a girl who thought that being fuckbuddies with the MC was perfectly fine even though she was technically with Chad still. There aren’t ‘two Sages’, but rather, there’s the slutty aspect of Sage’s personality and then there’s the loving aspect of her personality - as she says on the dance floor if the MC kisses her “How can you make me feel fuzzy and horny at the same time?”
I think the main issue comes from how the player playing the game reacts to a sexually liberated girl like Sage, rather than the character itself. Sage communicates her love for the MC through sex - the more she loves someone, the more kinky she becomes. This probably comes from seeing how her adoptive parents act when it comes to sex - Jade and Stephen obviously don’t fuck all that often, if at all, and it’s clear that their marriage is loveless as well. When Sage says she wants threesomes and to trust her with how kinky things get, she is really saying “Let me show you how much I love you by giving you everything a man could ever want.”
Even at the end, when the MC is like “Oh you don’t have to do the walk of shame”, Sage says that she wants to do it. Because to her, it’s not a walk of shame…she is PROUD that they fucked, and tells the other DIKs that they will keep fucking, so their stupid song doesn’t apply to her. She even goes as far as to tell them that they will be fucking other girls…sort of like a ‘fuck you’ to all the DIKs who were too afraid of Chad to pursue her the way the MC did.
Episode 9 reinforced to me that Sage is by far the best girl. If you want a sexually repressed simp, there’s plenty of other options.