Your strawman assertion is incorrect. It is not being asserted that the word of God is "in the Greek language only."
What has been clearly and soundly noted is that the preserved Scriptures in the original languages are the proper standard and greater authority for the making and trying of all Bible translations. The KJV translators themselves acknowledged that truth in their preface to the 1611. The translation decisions of one exclusive group of Church of England critics in 1611 did not replace and are not superior to the preserved original-language words of Scripture.
The same guiding of the Holy Spirit available to the pre-1611 English Bible translators and to the KJV translators (if they were believers) is still available to believers today. God is still the same today as He was before 1611 and in 1611.
It is asserted in Acts 2 at the beginning of the New Testament that the word of God is spiritual and is life because when the apostles preached it in 17 different languages at the same time, which included Hebrew and Greek, that which was preached to Hebrews only, gave life to those who received it and obeyed it. See here.
Acts 2:41 Then they that gladly received his word were baptized: and the same day there were added unto them (the apostles) about three thousand souls. How were they added? The Holy Ghost entered their bodies as a permanent eternal member as he did the apostles in John 20.
The quotes from the OT to the Hebrews were translated by God but there was no emphasis on one particular language Luke wrote the history of what happened in the Greek language but for the spiritual understanding of what it all means we will need to compare scriptures because he gives his word in precepts, here a little and there a little. Who would argue that what the apostles said in one language and heard in 17 languages was not translated by God. It was much more important to God that his word was heard and understood at this point than what language it was in. The confirming sign here for the Hebrews was the miraculous miracle of tongues. Remember, the Jews require a sign but the Greeks seek after wisdom. (1 Cor 1:22)
I think you are anti biblical in your philosophy and your insistence that God cannot give us his pure word in our own language when he began his age of salvation after the cross of doing just that. What we do not need is scores of men writing translations in their own words in the same language and after their own misunderstandings and calling it the word of God. This is the characteristic of these last days.