Thanks for the feedback :)
Many of the same things will still happen in both routes. Such as Nia losing in that scene, and getting Peni, but the perspective will be different. In the love route, it's fairly normal to take care of Nia, but in the slave route, this shows that he still cares. He may be abuse his power in the slave route, but he's never a vengeful master. This keeps the player character consistent across the slave route and the overarching story.
Cornwall hasn't flipped, he has just become more defined. When he was first introduced he made vague hints that he was more than who he appeared to be. That from your words, he had to prove you wrong so publicly and immediately.
The concept of Hope is something that has been on my mind since the start. Hope appears when faced with an insurmountable odds, and Lin's story especially has themes of hope for this reason. For the ending to be meaningful and impactful there needs to be struggle. The light shines brightest in the dark after all.
The player character is a self insert. I'm sorry you haven't been able to connect with him. I try to give the player as many different options as possible.
The manager wasn't passive, you just weren't following him. That day was from Ashley's perspective this time. It should be clear enough that he was doing things for Ashley.
I'm not sure where you would be getting the impression that he has no drive, or isn't able to lead. He has been shown to take initiative plenty of times, but the player character is also a supportive one, as the main characters are the 8 women. He is almost literally Nia's sidekick for example. But I don't know where this disconnect is coming from.
I'm also not sure exactly what you're pointing out in the Ashley event.
I haven't heard of that bug before, and because that content hasn't been touched in a very long time, it's likely this is a bug on your end and is a result of updating or something.