Two questions ...1. What does it mean (to you) that Yeshua is God's only begotten son?
2. Why do you believe that the begetting of Yeshua occurred at his baptism (i.e. what supports this belief for you) ?
Before I answer these and since I've already answered a couple of your previous questions. What are your views concerning pre-existeance of Messiah?
I think I'm ready to present an answer to your query here ... (I wanted to check out my scriptural support first)
I believe that the following passage of scripture testifies to the pre-existence of the Messiah ...Micah 5:2 But thou, Bethlehem Ephratah, though thou be little among the thousands of Judah, yet out of thee shall he come forth unto me that is to be ruler in Israel; whose goings forth have been from of old, from everlasting.
YHWH has always know His plan for Messiah. This scripture, again, doesn't prove Messiah is YHWH. Another retroactive reading. Why do you think the doctrine of the trinity wasn't required for salvation until 425 ad?