“The argument, “we should use the official Jewish Canon” is a thesis.”
That’s not my argument, it’s a logical extension of your argument. You say that Protestants should use the RC canon, because you “made” the Bible. Well, by extension, that argument means that RC’s should use the Jewish canon, because they “made” the OT. It’s your argument, not mine. I simply am pointing out where your logic leads.
Then you’ve not understood my argument. My argument is that the Septuagint, written by Jews for Jews includes these books. The earliest extant manuscript of the Old Testament is the Codex Vaticanus which includes these books and makes no distinction between them.
Ergo - I can conclude that we ought to follow the Jewish example in the Septuagint by using these books.