About the Battle of Wits and Courage Between Me and the Air After Obtaining the System

Shang Wu traveled through time and gained a system like all the protagonists. However, unlike those protagonists who were ecstatic after time traveling, he began to doubt the authenticity of his existence... Am I just a character in a book, and if so, am I a supporting character or the protagonist? Is it a single wear, double wear, or multiple wear? If it is a supporting role, is it a decent character or a villain? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.