The word doesn't exist in any text, whether Greek or Coptic (or Latin).
The oldest text that contains the full form in Coptic, is Melchizedek from the Nag Hammadi Library Codex IX, and this is in the very first line:
ⲓⲏⲥⲟⲩⲥ ⲡⲉ ⲭ̅ⲥ̅
Other than that we always find the brief forms ⲓⲏⲥ and ⲓⲥ - and when we do find ⲓⲏⲥⲟⲩⲥ, it means Joshua, as that is the way that Joshua is written in Greek - long before there was Christianity of any kind
When we observe Luke 3:29, part of the genealogy, we find ⲡϣⲏⲣⲉ ⲛ̅ⲓ̈ⲏⲥⲟⲩⲥ: the son of Joshua.
Yet when we observe Acts 7:45 and Hebrews 4:8, we find the brief form that is used for Jesus: ϫⲓⲧⲥ̅ ⲉϩⲟⲩⲛ ⲙⲛ̅ⲓ̅ⲥ̅ and ⲉⲛⲉⲛⲧⲁⲓ̅ⲥ̅ ⲅⲁⲣ ϯⲙ̅ⲧⲟⲛ ⲛⲁⲩ
The thing is, in the Christian texts we find these two forms interchangeable, even though that such occurs very rarely for Jesus, whereas Joshua frequently is written with the short forms that are exclusively reserved for Jesus. Coptic mixes both, even in one and the same text, while Greek almost exclusively uses the shorter form and Latin the longer. The longer form is earlier, certainly when it comes to ⲭⲣⲥ vs ⲭⲥ
And whereas Moses occurs more than a few times in the Nag Hammadi Library, Joshua is completely absent
So, to answer your question, my question would be: who exactly do you mean with Yeshua?
