Neither being powerful, nor reflecting the author is an insurmountable problem for a character. What you want to avoid is a character who faces no significant problems on her path to success, whose character flaws are all overlooked, and who is unjustifiably treated as intrinsically lovable. Self-insertion isn't the problem, it's the explanation. If it was intrinsically problematic to "insert yourself" into your work, no one would ever read autobiographies, and all the loosely autobiographical novels would have to be pulled from the shelves. Rather, "self-insertion" is a frequent explanation for poorly conceived, unrealistic characters who star in plots of interest solely to the author.

Basically, most readers, when they read a book, or watch a movie, want to be able to put themselves in the place of the main character, and to learn something from her story. Either they want to see her overcome a significant problem, or they want to learn what NOT to do in the same situation. But if the challenges are too easy, it feels like a cheat. We all know how to wish ourselves out of a bad situation, or how to fantasize a perfect scenario for ourselves. We don't need a writer to do that for us.

A super-powerful heroine isn't the most promising start for a compelling narrative, but there are interesting places to take it. Her biggest challenges are likely to be internal. Given how overpowered she is, you'll need to focus on her problems and her failures, not her successes. How does she keep from becoming a monster? How does she form real relationships with ordinary people? How does she maintain perspective? How does she deal with the boredom? The crushing responsibility? How does she keep from hurting people or destroying them accidentally? While few of us will ever actually be in the shoes of someone who is that powerful, we can still relate it to situations we do face in real life --getting a promotion, perhaps, or caretaking a child, situations that with intrinsic power differentials that can easily lead to abusive situations.

Neither being powerful, nor reflecting the author is an insurmountable problem for a character. What you want to avoid is a character who faces no significant problems on her path to success, whose character flaws are all overlooked, and who is unjustifiably treated as intrinsically lovable. Self-insertion isn't the problem, it's the explanation. If it was intrinsically problematic to "insert yourself" into your work, no one would ever read autobiographies, and all the loosely autobiographical novels would have to be pulled from the shelves. Rather, "self-insertion" is a frequent explanation for poorly conceived, unrealistic characters who star in plots of interest solely to the author.

Basically, most readers, when they read a book, or watch a movie, want to be able to put themselves in the place of the main character, and to learn something from her story. Either they want to see her overcome a significant problem, or they want to learn what NOT to do in the same situation. But if the challenges are too easy, it feels like a cheat. We all know how to wish ourselves out of a bad situation, or how to fantasize a perfect scenario for ourselves. We don't need a writer to do that for us.

A super-powerful heroine isn't the most promising start for a compelling narrative, but there are interesting places to take it. Her biggest challenges are likely to be internal. Given how overpowered she is, you'll need to focus on her problems and her failures, not her successes. How does she keep from becoming a monster? How does she form real relationships with ordinary people? How does she maintain perspective? How does she deal with the boredom? How does she deal with the crushing responsibility? How does she keep from hurting people or destroying them accidentally? What unexpected, hidden, or paradoxical limits to her power are there? While few of us will ever actually be in the shoes of someone who is that powerful, we can still relate it to situations we do face in real life --getting a promotion, perhaps, or caretaking a child, situations that with intrinsic power differentials that can easily lead to abusive situations.