You are right. The details of Prince Siddhartha’s life before becoming an ascetic have a few variations among different accounts by historians.
– Those details are not important for cultivating the path.
However, some key features are in the Tipitaka and those can be assumed to be correct.
– Those include leaving for the ascetic life just after his son, Rahula, was born.
The Tipitaka accounts are in the links that I provided in my first reply above. They can be assumed to be correct because everything else in the Tipitaka is self-consistent and correct.