John 20:28 - A Trinitarian Proof Text?

In John 20:28, where Thomas addresses Jesus as "my Lord and my God"?

Here Thomas addresses Jesus in the Vocative, which vocative demands the use of the definite article!

When lay Trinitarians, who are not familiar with either English or Greek grammar come back with John 20:28 as a Trinity proof text, it is done so in ignorance of the original language!

In Mathew 27:46 in the scene where Jesus is dying, he cries out, "my God my God..." here is the same, as in John 20:28, as, Mathew records what Jesus says in the Vocative, just like Thomas, and in Greek it is "thee mou thee mou", (the God of me, the God of me=transliterated). Also, in Rev 3:12, Jesus four times calls another person his God, "my God"

So, the question is, if Jesus is God to Thomas in John 20:28, then, just who is God to Jesus in Math 27:46 and Rev 3:12; also, it is of interest to look at Heb 1:8, 9?

If Jesus is God in v 8, then, just who is his God in v 9?

It is as the respected Trinitarian scholar "Philip B. Harner" says, that, ignorant lay Trinitarians when assimilating the term "God" in the God clauses in John 1:1, many slip into the heresy of Modalism, but, are not aware of it, all because, they assimilate the term God in John 1:1 (clauses, B AND C)!