Are the three 20-minute tracks in Digital Energy Acupuncture release identical? If not, could you describe the differences please?

No, each is different, though all are nature sounds that shift over the 20-minute period. You would hear a thunderstorm that eventually moves into an evening quiet with crickets, etc. There is also a sample on the Digital Energy Acupuncture page: https://www.iawaketechnologies.com/product/digital-energy-acupuncture.