But the personalized kind where the 3rd person narrator is not only focused on the main character but at times of conversation or intense feelings is just as restricted from „out of reach knowledge“ as the protagonist is.
Always third person, personally. I think first person can work, but it feels as if they are sitting down with you and recounting their life which works for some books but not all. Plus, imo, i think third person just flows better a lot of the time.