Hlo, hope you are doing great.

B.pharmacy and BDS are entirely different courses. We can't say which is difficult or what. It depends entirely on your interest.
In b.pharmacy you will learn about different medicines, their uses and composition not only that but also about cosmetics , daily used things , and their quality tests and much more. This course is mainly of chemistry field and has much scope.
BDS as name suggests is about dental field and surgery which is approved by dental council of India.
B.pharmacy is approved by pharmacy council of India.
Both of these courses has a duration of four years.

Best wishes