Quieter routes - not quite

Hi! I just tried out cycle.travel because usually I use bbbike, but that ends at the city limits of Berlin, so if I want to go on a longer bike tour, I need something else. However, I immediately noticed something: The route I tried out happens to go almost exactly past my old workplace, so I know the nice, quieter routes until that point very well. I was surprised that cycle.travel suggested a route that ignores any possibilities to use routes through parks and city greens that are away from car traffic and instead suggest that I ride along streets with heavy traffic instead. Even if riding through the park would be shorter. And I'm not talking about tiny paths through little parks, but about broad, paved ways that many people in Berlin frequently use as bike routes and still cycle.travel ignores them. As an example: We have a former airport, Tempelhofer Feld, as a large park where you can ride your bike over the former runways. Every cyclist in Berlin knows it, lots of people cycle there, but cycle.travel suggest that I go around it instead of across it along a large busy street. That's not a quieter route. That's a noisy one. And more far. If I ask bbbike instead and use the "green routes" setting, it gives me much quieter and more pleasant routes through Berlin than cycle.travel does. Can that be improved, maybe by looking at how bbbike does it?