my question is did Oprah let Weinstein and others use her to put other women at ease so they would be taken advantage of and was there an understanding early on in her carrier if she did this for the rich and powerful they would help her with her career goals.
The implied claim behind your question is unfalsifiable.
Unless someone comes up with hard evidence that Oprah, e.g., supplied the "roofies" (drugs to knock out the victims), it will be impossible to prove that she did anything but "try to help these young starlets establish useful contacts with powerful men in the industry."
Regards,
Oprah functioned as a Hollywood madam, introducing vulnerable and naive young women to powerful men. Probably told them that she could introduce them to these powerful men and didnt tell the price they would have to pay.