While it has been interesting to read the many varied and learned explanations why Revelation 3:14 does not mean that Jesus is God's first creation, I was struck by the comment that "while dictionaries are valuable tools for understanding words, they
often summarize meanings and do not capture the full spectrum of use in
different contexts". I think that is true, and wonder how the scribe who wrote Revelation 3:14 (or his exemplar) understood the Greek of his time which he had imbibed from his mother's milk.
Codex Sinaiticus was copied by three scribes who are commonly identified as A, B and D, and Revelation was copied by scribes A and D. Scribe D was responsible for the title and most of the first column (the first five verses), while scribe A copied the rest of the book.
What do we know about scribe A? He had a theological bias and was not particularly careful about his copying.
Apart from Revelation 3:14, there is a variant at Revelation 3:16, where instead of vomiting the Laodiceans out of his mouth (σε ἐμέσαι ἐκ τοῦ στόματός μου - referring to a human action by Jesus), he "stops their mouths" (παυϲε του ϲτοματοϲ ϲου).
At Revelation 5:13, where most manuscripts have the doxology to God and the Lamb of "the blessing and the honour and the glory and the might forever and ever”, scribe A replaces "and the might" (καὶ τὸ κράτος) with "of the Almighty" (παντοκρατοροϲ) so that the doxology reads that both God and the Lamb receive "the blessing and the honour and the glory of the Almighty”.
His treatment of sacred names is also of interest. These are names like God, Jesus, Lord which are abbreviated to indicate special attention should be given to them. He always contracts God (94x), Lord (25x), Spirit (22x), Jesus (9x), Christ (3x), David (3x) and Jerusalem (2x). In the case of Man (18/25) and Heaven (40/50), most are contracted, while Son is contracted 2/5.
In fact, codex Sinaiticus is unique in the number of corrections made to it. On the just over 800 preserved pages there are more than 23,000 places where the text has been altered. Most of these corrections are orthographical, in other words they involve spellings or graphical improvements. Even so, it does seem to show a certain freedom of speech displayed (primarily) by scribe A.
So the central question which no-one seems to want to answer is, if scribe A (or the scribe of his exemplar) did not understand Revelation 3:14 meant Jesus was God's first creation, why did he alter it?