Be careful as this is begging the question. You have here presumed that YHWH is the name of God the Father, when the OT only uses it of the being known as God.
Yes. And in 1 Corinthians 8, Paul makes a statement that shows that he believes Jesus to be God. More specifically, and as argued in detail elsewhere, Paul takes
this statement from the Old Testament:
Hear, O Israel: The LORD our God, the LORD is one
....and re-interprets it as this:
yet for us there is but one God, the Father, from whom all things came and for whom we live; and there is but one Lord, Jesus Christ, through whom all things came and through whom we live
In the Old Testament formulation, the descriptors "God" and "Lord" are clearly not
differentiated - this famous statement could, of course, be read as saying "there is one "god" and we give Him the titles "Lord" and "God". Fine.
Now what has Paul done ? He has taken the term "God" and assigned to the "
Father" and taken the term "Lord" and assigned it to
Jesus. Unless Paul is dismissing the Old Testament - and it is very clear he is not, Paul effectively analyzes
a previously "undifferentiated" Godhead and perceives (at least) two distinct persons within it.
I think it is important to note that just because the Old Testament is at best murky on the matter of multiple persons within the Godhead, this does not mean that Paul cannot
advance the Old Testament model and "update" it, not in manner that overturns the Old Testament model, but rather in a manner that exposes a previously hidden truth.