There are no Christian copies of the Septuagint.
What is codex Sainiticus then, and the many many other Christian copies of the LXX? This is so demonstrably false, maybe you mistyped or meant to say something else?
Christians did not produce the LXX, and the earliest copies predate the first century CE.
This is what I am saying. And none of those pre-Christian copies use KYRIOS. All of them use forms of the divine name.
Papyrus Rylands 458 contains only verses from Deuteronomy, and contrary to your claim, it covers verses in which the Divine Name is supposed to occur, namely...
Deuteronomy 28:17-19 and 27:15 and 28:2.
I did not say the verses did not contain the divine name. I said there are lacunae in the manuscript where the divine name or a substitute would appear. You can see this in the picture posted above, or read it in comments from scholars such as Howard, Pietersma, Tov and others.
Your claims that this is a product of the Christian era and covers no verse where the Divine Name should appear are quite incorrect.
I have nowhere said PRylands 458 is Christian. It is from the second century BCE so it cannot be Christian.
Please post any reference anywhere that says PRylands 458 has dots or spaces in place of the divine name.