“That’s not what the translators and scholars of the scriptures.”
Unfortunately for you - Sinaiticus and Vaticanus predate Jerome. They were also discovered after Luther. If your hypothesis were correct, then we would expect to see that the earliest manuscripts would not include them. But they do.
Same with the dead sea scrolls. If these books were non canonical, we would expect not to see them at Qumran. But there they are - right alongside the other books.
That to me suggests that if we were to come across a 1st century LXX manuscript that it would have these books there as well.
“Unfortunately for you - Sinaiticus and Vaticanus predate Jerome.”
Unfortunately for you, the scholarship of Jerome predates Sinaiticus and Vaticanus even if he is born later. The only thing those tell us is that they were included. What the scholars tell us is that they were included only because they were thought useful so far as edification is concerned, but not to be brought forward for the creation or defense of doctrine. That has been well proven over and over again, even if you ignore it. Same thing with witch craft and their contradictions with history and the scripture.