You would have to come up with an explanation for such drifting to be occurring across the entire visible universe in precisely the same way, across billions and billions of light years.
With the direction in which we are traveling at c called “time”, and the other three which we're not moving through called “space”;
diverging rays having spatial velocity relative to each other equal to tan(alpha) i.e. flat projection;
and at any given point on the 4-sphere's 3D surface everything appear to be diverging in 3D because the emission is spherically symmetric;
and trajectories sufficiently paraxial to us fits the small angle approximation but those diverging widely has much more apparent perspective distortion,
with an error ratio of tan(alpha)/sin(alpha) = sec(alpha) = 1/Lorentz_Factor?