I think the real issue here can't be resolved by an examination of terms - it involves a power dynamic where Uber contractors are extremely at disadvantage when it comes to being able to set your own rates. I don't know if Uber even has someone on staff that's qualified or expected to negotiate with independent drives that are interested - they have a posted rate that you either accept or they walk away. And, the worst part, they change that posted rate for BS reasons constantly in a way that people can't predict, it makes for an unreliable and misleading income.
They don't just let you go in demanding whatever you want. There's a limit to what they want to pay. Just like Uber.
You can absolutely go in and demand whatever you want. If you ask for 3x, you probably won't get the job. But 5% or 10% over x? It's possible. I don't see how contracting is 'locked in'. You are certainly free to negotiate, unlike on Uber or Lyft's platform.