Sorry!
Well now I feel like an ass!
Come on, it's not that bad - the overarching plot is great! Visiting your hometown after leaving is a very good basis for a story. It's a topic people have opinions on, so they get engaged with the plot. That is good!
But! You do need to work on your banter game. It's pretty hard, it takes some skill, and it takes time.
To your credit though, you already nailed something that gives a headache to most beginning writers. And that's making characters sound distinct. They all need to have a character and a manner to their speech, and that's exactly what you gave them! Well done!
Now! You just need to understand that people in books, movies, and VNs don't just talk the way you and I do. Why? Because we don't have an audience. And your characters - yes, they do. They have hundreds, potentially thousands of people watching them, waiting to be entertained. So entertain them.
Think back to movies that had great banter, think back to books that had episodes about nothing that still kept you captivated. What were they doing that kept you interested?
They never wasted a line.
Everything was piling up on what came before, building up to give you a resolution. They set something up in the beginning and then circled around to it in a smart roundabout way. Every great banter scene was a slow-burning joke that made you think.
I don't mean that you have to turn everything into a comedy routine, but you need to understand how to follow those same beats to keep the audience interested.
You decide on the goal of a dialogue, you set up an entry point, but don't make it too on the nose. Then develop it, have characters discuss it, rub their characters against it. And then, in a smooth motion, do the punchline. It doesn't actually have to be a punchline, just a satisfying resolution.
You actually had a good dialogue like that - Rebecca talking about why she does everything she does. You just needed to cut it shorter. When she says "I couldn't do any of those damn speeches without Oliver. I don't know what I'd be without him. But without me - he'd be dead."
That right there is a perfect moment to cut. It's a heavy line, a good punch line, it makes you think, it has weight, and it closes up the topic naturally. Why is Rebecca doing it? Because her friends would be gone without her. Now make the characters shut the hell up and wrap up the scene. You don't need Rebecca explaining herself any more, you don't need the protagonist interjecting. The topic is already closed, do a wrap-up, trim that scene.
p.s. Please don't feel like I'm telling you off or putting your writing down - I wouldn't even bother leaving a comment if I didn't think you can fix and improve what you have here. I do wish you the best of luck with it, you're definitely onto something great here, it just needs a bit more work.
p.p.s. NEVER roll over like this to criticism, even a fair one. If you keep working on your VN - you're going to meet a lot of self-important nobodies actually trying to put you down. I mean, hell, you have an autistic approachable girl in your VN, someone is absolutely going to have an issue with that. Do not roll over when they come.
You're trying to tell a story, you're doing your best to make it good. If someone has an advice - good, if someone has a problem - there's the door. Again, good luck with your project.