Question

are all Ōtsutsuki's evil?

Answer 1

No, not all Ōtsutsuki clan members are necessarily evil. While many Ōtsutsuki characters in the Naruto series are portrayed as antagonists, there have been exceptions, such as Hagoromo Ōtsutsuki (the Sage of Six Paths) and his brother Hamura Ōtsutsuki. Ultimately, whether an Ōtsutsuki is good or evil depends on their individual beliefs, goals, and actions.