What's the alternative? Gravity? Are you claiming to understand the "why" behind that?
No, I can simply provide more tangible evidence and a more reasoned explanation than you can.
We can calculate the movements of objects based on theories of gravity to an incredible degree, through mathematics. From planets to comets to rocks, the movement of all these things can be calculated given the right information. I genuinely doubt anyone on this forum can do so through a theory of dark energy.
Also, if dark energy moves the entire Earth & cosmos upwards at the speed of light, then by that logic, when I throw a ball into the air or fire a bullet into the air, that bullet must be breaking the speed of light, in that it is moving faster upwards than the Earth, which itself is supposedly traveling at the speed of light. That would break the fundamental laws of physics.
And I would still lke someone to explain why there is a discernable curvature of the Earth.