They can't. They. Just. Can't.
I do not believe the Word of God shows anything but that the globe of waters was created first, with no heavens stretched out from the earth, between the cut in two waters, and the Light right here, circling this globe from day 1 of creation week, and stretched out with the firmament of His powers on day 2 of creation week, between the divided/cut in two primal waters of this globe: but you are correct that the math used by those who make such statements as the distance of nearest "star" from earth cannot be proved by earth based math. The entire heavens were stretched out, with the light, from this globe, between the waters.
They are foolish and know nothing who make such statements as if they know it as truth.
The stars themselves will all fall to this same globe, right down from the heaven they are set in, at the end of this present age,
and then the "wisdom of men" will be shown, again, to be nothing.
Co 3:19 For the wisdom of this world is foolishness with God. For it is written, He taketh the wise in their own craftiness.
The entire creation was supernaturally created by a supernatural God by His supernatural Word and is upheld by the Same Supernatural Word who created all things in the beginning, when there was nothing, but Himself, in 3 Persons.
No heavens were "out there" on day 1 of creation week. Just a "firmament of His powers" and a globe of primal waters suspended in the same, and darkness. Then Light, brought out of the darkness, and the darkness and the light circling the globe, making one full Day in the completion of their circles from starting point and back to the same.