I didn’t say that. The story of Abraham in the Bible/Torah begins with God instructing Abram to leave Ur and go. Does it look like Abram needed to “convert” from the worship of another God or does it look like he was simply worshiping the the God of his father and grandfather and so on?
You clearly missed the convenent, a rather bloody scene, involving torn animal bodies and genital mutilation.
He even took a new name, which is what you do when you convert.
That said, the point being Jews-by-Choice must be treated the same as Jews-born-of-a-Jewish-Mother is expressly stated about twenty times in the Torah.
In fact, one may not remind them that they converted, as that is a violation of the Law.
Some of the best Rabbis, ever, were converts.
Period.