And Sankara had many ideas that were similar to Buddhism, like disdain for rituals, liberation through knowledge, disregard of caste hierarchy, etc.

He was later attacked by rival Vedanta schools for being opposed to rituals as rituals are central to the Vedas.

But he did attack Buddha and Buddhist ideas. The point of conflict was the existence of self.

But he used many strawman arguments, and criticised Buddha for saying things he didn't say. Sankara didn't know and didn't care.

He was a great philosopher, though.