metis
aged ecumenical anthropologist
That is correct and in those "commentaries" is the evidence of the changes made to the original text. And as you can see, the motive for the Sopherim to make those changes were much more logical than for Christians to disclose them.
First of all, exactly where does it say in any commentary that "Adonai" was changed to "Y**h"? It's far more likely, I would suggest, that maybe the commentary, even if it exists, either was giving praise by using the "Y**h" or may was making it clear that Adonai was referring to "Y**h" since "adonai" can be taken in different ways.
Could you please provide the exact wording of that commentary, plus provide a link in Hebrew to it?