You have to think reference frames here, not timelines. A reference frame is a coordinate system. Usually with 3 space-like coordinates and a time-like coordi

You have to think reference frames here, not timelines. A reference frame is a coordinate system. Usually with 3 space-like coordinates and a time-like coordinate we call "time". That last coordinate is what gives meaning to "now" between two distant places. But this meaning entirely depends on the reference frame chosen. In Special Relativity, there are special reference frames called "inertial reference frames". From these we can easily calculate elapsed time for any particular path through space-time. In General Relativity it is harder - there are generally no inertial reference frames to be found. But we can still do the same calculation using tensor math and something called "the metric". You can actually do the same thing with special relativity, however the metric is dramatically simpler in an inertial reference frame so people usually take the easier approach. The various measures of "curvature of space" are measurements of how quickly any attempt to describe space-time an inertial reference frame will be wrong. Just as the curvature of a ball makes it impossible to properly describe its surface as a flat plane. (Mathematically this description is very precise.) Now in a low gravity situation, we can find inertial reference frames that are approximately a match. The almost inertial reference frame where the distant galaxies are moving straight away from us is the one we usually implicitly think of. In that reference frame, this light was emitted 26,000 years ago. But you can pick a reference frame that gives literally any answer that you want. But that reference frame is a bad description of the experience of timelines for fast moving objects, or what is happening in deep gravity wells. However that is fine, since from that reference frame we can predict exactly what the experience of those timelines will be, and our predictions turn out to be correct.