Although it is an editor’s job to catch all of your mistakes and omissions, editors are still human. The more overwhelmed they are with all the little things that you could have fixed yourself, the less energy they will have for the things you wouldn’t have caught. Help them to help you by making your manuscript as clean as possible.
How do you run a marathon? One step at a time. Any major project takes time, commitment, and consistent effort. You can’t just snap your fingers and have a completed project. But you can create big things one small piece at a time.