If an object is moving at constant relativistic velocity (not accelerating) and you are moving alongside the object in its reference frame, then you are at rest with respect to that object. Newton’s laws then apply.
So apart from acceleration, gravitational fields, (an event horizon has both) and separate reference frames, yes I would agree with you : )
What are you trying to show though? That something in a steady state relative to yourself is in a steady state relative to yourself? That doesn't seem very interesting to me. It also doesn't prove any of Newtons laws either.