What is Yahweh’s name (Hebrew) translated into Ancient Greek?

There was a taboo on saying YHWH out loud in Hebrew, and that extended to other languages; so yes, the Septuagint rendered YHWH as Kyrios, the Lord, just as Jehovah (when Christians rediscovered YHWH) comes from YHWH with the vowels of Adonai.

Now, Jehovah has come into Modern Greek as Ιεχωβάς, /iexovas/. Jehovah’s Witnesses, for example, are Μάρτυρες του Ιεχωβά. But Jehovah is a Renaissance coinage in western languages.

Did any Greek writings render YHWH?

Well, some Greek theologians discussed YHWH as YHWH. The Hebrew יהוה looks like the Greek ΠΙΠΙ. Hence the work spuriously attributed to Evagrius Ponticus “About PIPI”—although if you read it, pseudo-Evagrius knows perfectly well what a yod and a he is.

We also know that Theodoret (Quaestiones in Octateuchum p. 112) said that the Samaritans pronounced YHWH as Ἰαβέ, /iaβe/. He says that Jews instead pronounce “I am that I am” as Ἰά /ia/, which is of course just Yah. Epiphanius of Salamis‘ Panarion also mentions Ἰαβέ “He who was and who will forever be” as one of the many Jewish names for God

The Greek Magical Papyri are full of referenced to all manner of deities, including Yahweh, but only once or twice as Ἰαβέ. Their usual way of alluding to YHWH was Ἰαώ /iaɔː/(Iao – The Encyclopedia of Ancient History – Pleŝe – Wiley Online Library ).