One of the greatest lost opportunities of globalization is that we’ll never get to see what wild and wonky syncretic versions of Christianity might have emerged from isolated Christian sects in Korea/Philippines/China etc
And by a Chinese legend I mean its an icon of Jesus painted by a Manichean sect in southern China, that was then brought to Japan and used as a Christian icon by Arima Harunobu, and now it’s in a Buddhist temple and venerated as an image of Ākāśagarbha
Most archeological, anthropological, and comparative religious research says "no". They're one of the early religions Christianity was competing with, which did borrow elements from Christianity but only because they borrowed from everything on the Silk Road.
Yes, and Buddha was some form of Hindu before becoming the Buddha, does that mean Buddhism is a form of Hinduism? Is Christianity a form of Judaism? Is *Islam* a form of Judaism?
Is Manicheanism a form of Judaism, for that matter?
You probably could define Buddhism as a derivative of Hindu practice honestly, if only because so many core ideas are clearly in conversation with Hindu concepts