Thank you for your feedback! It's so weird that you're not passing the art dealer scene... That part has been thoroughly tested and I never found a problem with it!
Anyway, and although I do love stat-raising games (Long Live the Queen is one of my favourite VNs, and you must definitely play it with the guide open on a different tab if you want to reach most of the endings), it's obvious by now that most VN players dislike them. To be honest, Night and Day has been hellish to code, and it's the part that delayed the release for a whole year. On top of that, even with lots of playtesting, bugs are still happening, which is as infuriating for me as a dev as for you as a player :/ So I can assure you my next games won't have any kind of stat-raising system, and will focus only on the story, and choosing different options for the characters.
The only thing I can do by now is lowering the stats requirement for the art dealer in the next update. I hope that will help with the game's enjoyment, even if it's a little bit.