I have to agree with most opinions about the writing being not so good, but I wouldn't say it's awful and there's definitely still ways to fix this.
Inner monologue being overused is the obvious issue because it is basically telling the players what's happening in writing. It's great for a book where it helps the reader to imagine what's happening and what the character is thinking, but it's less effective in video game format because the advantage of being a game is that it doesn't have to rely on the player's imagination. The game can actually show these thoughts and it doesn't have to tell the player in writing.
The other problem IMO is the breaking of the fourth wall as well as real world reference. Choosing to proceed with Sakae or not, it shouldn't be followed with dev's comment which really breaks the immersion. Real world reference can be ok if it's done well, but just like the inner monologue, I think the writer ended up putting too many of those.
Next up is the whole non-English words but without context. "Lillasyster" is such an annoying word to use when there's no context. Yes, it's easy enough to guess that it means "little sister", but why is a Florentino (that sounds Italian) using a Swedish word like that? Then of course it continued with more Swedish, Japanese, and then Italian for some reason. What started as small annoyance of using non-English ended up being poor character portrayal because multi-lingual people don't actually switch between languages for sentences like that. They might switch languages depending on the other people, or if they can't find the right word in one language, but they don't speak English for one sentence, then Japanese for two sentences, then Italian for three sentences, and Swedish for another few sentences like that.
Lastly, it's also jarring to play as an MC but being somewhat irrelevant in scenes. It's like the other characters would talk while MC just stayed out uninvolved and/or being unresponsive even when they were talking about him.
I'll end this post in a somewhat more positive note. I think the plot is quite good, and I think the characters are quite interesting. So the core of the game is pretty solid. With improvements on the writing and presentation, this game could become much better. Here's hoping for a better next version.