That is an inference you made. Conceive of space however you want. That doesn't change the facts of observation. The universe is expanding at an increasing velocity. That means a force is accelerating it. Hence the need to theorize the existence of dark matter and dark energy.
Theorizing about dark energy and dark matter is trying to force the geometro-dynamics of space-time into a bed of Procrustes of concepts we devised to describe interactions of matter and energy, not changes in space and time themselves.