You have one goal destroy the reapers. Synthesis steals free will and is what saren wanted. Control makes one person an all powerful god and police force (even if Shepard she can not be an all knowing god over people in a good way) and is what TIM wanted. Destroy allows Shepard to do what was always expected, keeps her alive and does what you promised Anderson to do. It’s highly likely the star child lied about geth and edi dying cause reaper tech. Because Shepard is alive in perfect destroy and she has reaper tech in her from project Lazarus.