I agree with you that any expression of G-d as a multiplicity, such as wideawake’s understanding of the Ein Sof, is not a Jewish concept and, to a Jew, is heretical. That is where I was going with my questions.
During a class by a famous rabbi (noted for his contacts with Christian clergy and his tolerance of alternative views), I was shocked when he remarked off-handedly that one of the main occupations of Christian theologians was “telling big giant whoppers”!