I think it might be a good idea to focus on one branch to begin with. Not exclusively, necessarily, but a lot of people prefer stories with a bit of depth to them, and naturally they look at chapter depth as an approximation to that. For me, if I were just browing the site casually to look for a story to read, seeing only '4' there would be a bad sign. Making your chapters shorter will also pad out your numbers, but there's
little consensus on how long chapters should be. Yours are definitely on the long end of the spectrum, though.
This might be an interesting article on how escorting works:
https://knowingless.com/2021/10/19/becoming-a-whorelord-the-overly-analytical-guide-to-escorting/ It's US-centric, but I assume most of it applies widely in the western world. Of course, Aella is an experienced (ex-?)escort, and Dawn very much isn't, so you almost certainly shouldn't have her adhere to all the principles Aella outlines, but it might still be useful background information for you.
I assume it's already been changed: the current image looks perfect to me. It's exactly the kind of picture Dawn would've used as on her public escort profile. It's subtle, I like it.
For the rest of this post, I'll focus on the Marvin branch, which seems to be the most developed branch:
Dawn clearly does not enjoy being an escort, and I think that's the thing I like most about the story. It makes this more a drama and less a Sexy Sex Story for Masturbation Purposes, and really makes it stand out among the crowd.
The extended background information you include for Marvin felt a little overkill to me. I skimmed over a lot of it; after all, at this point, he's just a customer. I feel like it could've been a single paragraph. If you do plan on having him come back later on in the story, you can sprinkle more details about his background into the story then, when the reader has started caring about him. (Or, as the case may be, has started hating him.

)
I think you're trying to hint early on that Marvin is not as nice a guy as he pretends to be, which is a great touch. To me, though, it felt less like he's hiding a dark side than that his emotions are just all over the place. One moment he's treating her genuinely pleasantly and positively, talking about his life, and taking the time to really get to know her. Then he turns forceful, while remaining positive, such as when he practically commands her how to get her life back on the road. And then another few paragraphs later, he suddenly swears at her and calls her a newbie, and in both the hotel room and egg branches, forces her to do things she's clearly not comfortable with. He makes it clear Dawn is far from the first escort he hired, so I feel like he should be better at hiding his abusive side... but only from Dawn, not from the reader! It's a tough problem, especially in third person limited.