(if there were a way to do a partial brain transplant which carried memories
Years ago, I saw an interview with a woman on TV. IIRC, she was the first recipient of a heart and lung transplant.
She was asked a question shortly after surgery in which her reply was something like "I'd love to have a beer!" though she did not drink. The young male donor who died in a motorcycle accident did drink. She also reported having dreams and other experiences in line with having somehow inherited some piece of his consciousness. Over time, they faded.
If anyone is curious to read more, this might be her book:
A Change of Heart: A Memoir by Claire Sylvia