You know nothing but how to fabricate fairy tales. I can only imagine who these "others" who taught you were. There were Jews exiled under duress to Babylon. In the year 423 BCE, the Babylonian king Nebuchadnezzar lay siege to Israel and laid waste to the city of Jerusalem. His soldiers forcibly marched 10,000 of the most elite scholars and religious leaders to Babylon, to exile. The common folk were left under the rule of King Zedekiah. A rebellion against the rule of Nebuchadnezzar arose. The prophet Jeremiah begged the people to stop their rebellion, but they would not listen. Nebuchadnezzar set his soldiers upon them and crushed the rebellion, sending this remainder of the Jewish people also to Babylon. Jewish communities then arose in Babylon, with great scholarship in Torah.
The Five Books, plus Prophets and Writings make up the Written Torah, while the Oral Law is a legal commentary on the Written Torah, explaining how its commandments are to be carried out. Without such explanations, the observances specified in the Written Torah would be rather vague to be able to follow. The Oral Law is organized into sections of Jewish law making up the Mishna. The Mishna, plus the commentaries and discussions of it (the Gemara), together comprise the Talmud.
Kabbalah is not to be confused in the way you present. Kabbalah is the mystical aspect of Judaism, and is only to be studied by the finest scholars of the Torah. For the average Jew, the requirement is to observe G-d's delineated Mitzvos (precepts) to the best of their ability. In no way is there any belief in a "different Supreme Being"! That is pure blasphemy. The ein sof is a name given to G-d which refers to His aspect which is apart from the world He created; His pure essence. It is a term used by those who endeavor in the study of Kabbalah.
It doesn’t appear we’ll be able to agree on this, but the definition of supreme is to exist on a higher level, and in these teachings, this supposed entity ein sof is on a higher level of existence than the God of The Bible. These teachings were conceived centuries after The Bible, as well, which lead many to believe they are the blasphemy, not The Bible. Obviously the debate won’t settled here, but my my framing of it still appears accurate to me. Have a good day.
The Torah is simple to understand. When the New Year starts, on the sighted moon, then the calendar unfolds. The Holy Days are known and follow. The Jews screwed up their own religion, and use precedence to make Yehovahs law void. They will see their “rewards and treasures” by their works. They have no faith as a group. Most don’t believe in their Creator, or the fact that all the world comes from the intention of Yehovah.