You might find
this post by Aly of some interest. There's nothing the game can really give you right now for not romancing Kas other than to say 'Okay, you're not doing that'. Will it influence the possible endings you can get if you're dealing with Hostile or Lustful Kas instead of Romantic Kas? Practically guaranteed. Will someone sit down and write an equivalent amount of content exclusive to a Hostile Kas playthrough that her Romantic route has? No, almost certainly not because what are you going to do? 'You sit there, thinking smugly that at least unlike the Champ in the universe next door,
you're not banging the omnibus and you feel good about yourself for that'?
There is content that reflects those other two states including the just-added Mayternity update for Aileh, where how Kas reacts to Freja's birth depends on which of the three states she's in. But I wouldn't go expecting special content just for those routes.
But I feel there wasn't EVER a single shred of feeling or love up until that point in the story.
Handling feelings for blobchamp is very difficult because the writers need to walk a fine line between conveying what they're feeling and not stepping too hard on the toes of people who want to roleplay their Champs in certain ways. The assumption is that if you willingly have sex with Kas on
multiple occasions there's more to it than the Champ just being horni for her. One time, sure (especially in the tutorial when you could chalk it up to Portal Fuckery) but if you keep doing it when you're free to say no...
Also, one of the events that raises your relationship score is Kas trying very hard to be romantic. It's possible to not see it before Winter City depending on when you play the game and whether you turn seasonal events to always-available, but it's there.
