Who Considered Buddha as a Vedic Yogi/Guru?

[Duvduv]

Someone has suggested to me that the true teachings of Gautama Siddharta involved him simply being a reformist who opposed accretions onto Vedism, and that in fact he was simply a guru/yogi in the original Sanatana Dharma religious tradition, but that over time it was changed and moved into the realm of being another movement after the days of Ananda and Negarjuna who added new teachings. Has anyone studied and written about this?

[Duvduv]

Where is it stated in the earliest teachings of Gautama Siddhartha that he rejected outright the Vedas and the idea of Brahman/Narayana/Ishwar??