You lost me a bit. But I see your point regarding light in a straight line through “curved” space.
Assumptions: Our galaxy is moving in space. Our galaxy is rotating as it moves through space. Our solar system is in one arm of our spiral galaxy (in rotation). Our solar system is moving within that arm of our galaxy with our star being at the center of the movement. Then our planet is moving around our star. If observed from a stationary point in space (no idea how you could determine what that would be), how would our planet be observed as moving in a straight line. Could the distance our planet has traveled be measured from that observation?
Similarly, If light is observed from a single point in space, in a straight line, and the light travels along a curve in space, that we cannot see, how is the red shift affected as component of the distant the light travels before we see and measure it? We determine distance based on how far light has traveled at a constant speed. Does it not suppose that light traveling through curved space (gravity) would travel farther, and thus corrupt the data?
The easiest way to imagine it is a bowling ball sitting on a foam cushion.
The foam represents space- he ball represents how a ‘mass’ distorts it, and the space curves around it.
You can easily see that if you roll another ball around it, the curve will allow the ball to circle the bowling ball.
1) EVERYTHING is measured relative to where you are standing. The measurement of the same object you take would be different than the measurement of some one moving (relative to you) - but remember, to him he is standing still and you are moving. That’s what ‘relativity’ is all about.
2) there is nothing about the ‘path’ through curved space that affects red-shift. Only if something is moving towards or away from you.