Bhagavad Gita Chapter-2 is one of my favorite ones, as it covers everything Shri Krishna wanted to tell to help Arjun overcome his delusion.
Chapter-3 onwards exists because Arjun had questions. To answer Arjun’s questions Shri Krishna provided more information in other chapters. Finally, chapter-18 summarizes everything.
So, chapter-2 is not a summary of Bhagavad Gita, but it covers everything Shri Krishna thought was enough to get over the situation of confusion/delusion.
Given that we all are in Arjun’s situation most of the time, hopefully, this study will help.