If I had to sum up my impression of what's kind of meh about this manga...
The mangaka probably thinks of Himari as a self-made princess and raises her up, acts like little compliments from her are supposed to be something amazing, and expects the readers to feel the same way.
But that doesn't work for me, because Himari just feels like a person with a slightly self-centered (understandably, she runs her own business) mindset and a good work ethic, and a normal personality... not the personality of a saint or a two-faced villain, just a normal girl.
Nothing she has done has made her feel like a "character out of a manga" to me, aside from the tsundere speech patterns. She's not uniquely kind or selfless or considerate in any way, she's not uniquely clever, she doesn't have some incredibly deep or unique conviction or goal besides her career/passion for fashion that we've only seen a little of. She's not in some unique circumstance besides wanting to avoid others' excessive attention which is just normal. Her connection to the protagonist is just classmates and employee/employer, the secret is also one they share not because of trust or respect but because they are being professional with each other.
The male lead is, of course, even more normal than her, just a high school boy with a work ethic that's well above average. In short, this story is incredibly normal to me and it feels like there is no factor that strongly appeals to me. The character with the most "manga character energy" is Honoka because she (presumably from the last page) is consciously aware of her romantic feelings for another character.