It's also much older than Hinduism. The earliest known example of a swastika was found carved into a mammoth tusk from 15,000 years ago. It represented the powers of fertility before it became hijacked thousands of years later. Hitler borrowed the symbol from the Aryans, a real people that lived in India before Hinduism was introduced. This is why the SS sent expeditions all over the world, including Tibet, to hopefully find a link between modern-day Germans and what was then known to be the oldest race of people in history.

More specifically, the swastika represents the union of male and female reproductive organs. Essentially, fertility worship lies at the heart of history in every culture, as it's the most basic requirement for humanity to continue existing.

https://www.britannica.com/story/how-the-symbolism-of-the-swastika-was-ruined