Hah I'm on both my dude. I have two playthroughs presently - in my first & primary playthrough I went full Bella route, BUT we haven't seen anything with Amber yet, really in terms of relationship development, so I could absolutely flip 100% to Amber depending on what happens. Amber is by far the most physically attractive woman in the game to me (so far, at least).
So I ended up creating a 2nd playthrough where I mostly reject Bella romantically, but try to be friendly enough with her to not be enemies, and expressed some interest in Mila (to hopefully drive a dating route with her to explore as she has a killer body as well) but primarily I wanted to keep Bella at a distance in order to go balls to the wall with Amber when that route opens up.
I am open to having my mind changed, though - the fact right now is that outside of Bella and a tiny bit of Nami & Mila, we have minimal relationship development with other girls in the game so a lot of things are going to remain fluid for a bit in the story. We're only through chapter 3.5 of a ~30 chapter story, so many things can and will change. If things develop in such a way with Amber or another character that I develop more interest in for whatever reason, I may end up scrapping things with Bella or someone else. Just like IRL, when things happen or people do certain things, it can change your perception of them along with relationships, so I try to remain open minded this early in a story or any 'relationship' with someone since there's so much we don't know about these characters to this point.