Apologies for the second comment but, some suggestions after playing through, if you didn't mind.
Kuno's backstory is actually a bit reminiscent of the player's own backstory, with them feeling like the only thing they could provide or do well was 'servicing' others. I know the game is mostly about kinks, but a moment where the PC tells Kuno that they understand how it feels to feel like they're only skill was servicing others would be a nice little exchange or even just a nod. You know sort of acknowledging how both the PC and Kuno seem to have dealt with similar circumstances. Maybe even talk a bit about what it's like being looked down upon by their peers and they're experiences in being a cocksleeve for the many people they serviced. I think that could make for good bonding moments between them!
I tend to like to play my Captain as a relatively naive and well meaning person who tries to overcome what seems like the world putting him down and ruthlessly fuck him, so I always like to try to be uplifting and thoughtful when I can. Having more options to try and treat Kuno as a companion and maybe help uplift them or see more value in themselves would be nice!
Generally speaking I really love the bits in the game that develop the player character and companion's personality, feelings and thoughts, even if it is brief. I honestly really liked one of the texts that popped up when the player chose to sleep alone, and described the player recollection of their life on Vulpis and how they were constantly insulted and belittled, with the dream ending in the character waking up frustrated and unhappy. I'd really like to see that aspect of that character's personality, the frustration, the despair and discontent at how unfairly he's treated pop up more. I think it's a really interesting fold to the character that would be very fun to see appear. Life's tough out there for a girly fox boy after all, hard not to start losing your cool sometimes!
Some of my favorite content is on Procya and the cowboy planet. The emphasis on loss of control, fear and pain was enjoyable. I'd love to see more of that content again maybe with an added emphasis of fear and anxiety flooding his mind and having that clash with trying to retain composure and not break could be fun. Perhaps there could be a bad ending that's triggered through the player character being particularly mouthy, snarky and frustrated with somebody who just seems to continue to push his buttons by belittling him and looking down on him. Maybe something about the player character being a useless girly discksucker who's only skill is sucking cock would set him off. Something that maybe hits too close to home, causing him to mouth off back to the person haranguing him. I really like the idea of the player character having some insecurities about himself and that leading to problems or bad outcomes, I think it could be a really fun direction for some future bad ends. (Andelaar on Procya is a great candidate for that!)
Having the player character also be referred to or treated as as a femboy, thus causing him to be treated differently for some scenes with the wide hip mutagen would also be really fun! I'd love maybe a handful of scenes and maybe even some exclusive femboy themes to be unlocked with that mutagen.
Sorry for the load of text there, just a few suggestions I wanted to share!