I’m not sure why you’ve put confidence in the oneness teaching based off cherry picked verses. When Christians assert the Trinity, it’s based off a full understanding of God’s revelation in Scripture.
Now, what I do appreciate about your arguments is that you’re going to the text instead of making strawman arguments like the other guy in this thread – he likes to assert a falsehood and then attack that. No Christian believes in 3 separate gods but in one God revealed in three persons. It is a mystery beyond full comprehension but it is something that can be apprehended.
All that said, l would agree with your statement at the very top of the page and the text you’re using is indeed speaking of this mystery. Every pronoun refers to a proper noun. In the case of the verse you chose, there are two proper nouns. That is because the author is making a significant distinction. If oneness modalism were true, there would be no reason for this distinction, especially in this case, since this is the throne room of God.