When we’re traveling in a car, we certainly can tell we are moving, so in what sense can we claim to be at rest?
So, if all motion is relative, does the Earth go around the Sun or the Sun go around the Earth?
You didn't use the language of 'inertial' frames in your discussion, but I've heard they're relevant to the ideas you are covering. So, what is an inertial frame, and why do they matter?
What is the litmus test for being in an inertial frame?
When we are at rest on Earth’s surface, are we in an inertial frame?