The main lesson to be learned about the struggles between Yakov and Eisav, is to understand their essences.
Eisav showed his true colors with his willingness to sell the birthright for a bowl of lentil soup. He had the philosophy of eat, drink, and be merry, for tomorrow you die. He was not at all spiritual. Everything was about גשמיות and material pleasures.
Yakov was the opposite. His life was devoted to the spiritual and serving Hashem. He realized the temporary nature of this world, and how there must be an עולם הבא. Their difference was simply that Eisav was materialistic and Yakov was spiritual.
People are frustrated when they have so much materially but happiness alludes them. Selfish pursuits never lead to contentment. Selfish people are unhappy people.
Giving selflessly to others, brings joy. We are meant to follow in Hashem’s ways. Just as He constantly gives, so must we. Yakov understood this and became a צדיק. Eisav did not and became a רשע.