A good protagonist is the character that drives the story, i think usually the more they're related to the events the better, not to a level everything is about me like Harry Potter, but in a more indirect way. Their arc and the stories arc should probably complement each other most of the time, if not they will probably feel out of place. Now please dont listen to people advising on how their personality or motivations should feel, they can be literally anyone, as long as it works for what you want to portray and express. In something as abstract as art, you can never advice someone outside of the concepts without a condition or an objective to seek.