I cannot see any way that an absolute at rest frame of reference is possible.
I cannot even see a way to construct a locally "at rest" frame of reference by averaging all potential frames of reference, as it would seem, to me, that unresolvable conflicts would arise between any imagined averaged frame of reference and one or more of the "possible" inertial and non-inertial frames of reference involved.
As I attempted to present earlier, the closest thing we can currently observe, to an at rest frame would be the CMB and in that we can only know what it looks like from where we "are". If we were to consider the CMB, as we measure it, as representing an at rest frame of reference, we have no way of imposing it on portions of the universe outside of our own frame of reference.
In a way, any attempt to define an at rest frame of reference from our own perspective, elevates "our" frame of reference to a preferred or special status.
Setting aside the specifics of general relativity and its treatment of space and time, the GP-B experiment does demonstrate that space or what we experience as space is at least locally dynamic. There is no reason to expect that the local dynamics of space is special. (i.e. frame dragging occurs and is centered around the Sun, Earth, galaxies and even galactic clusters, each an independent frame of reference involving both mass and space in a unique inertial relationship.) Given that our current understanding is that inertial and non-inertial frames of reference involving objects (matter) must be considered equally valid and that as per the results of the GP-B experiment space follows similar rules relative to a frame of reference. There is nothing conceivable which is kinetically static, at rest or absolutely stationary.
Relativity does appear to be a fundamental aspect to the universe in which we exist, which includes both the matter and space, as we understand them.
Unless at some time we discover this to be contrary to experience, there is no preferred frame of reference. No "Absolute-Static" frame of reference. All frames of reference are relative.