Your question is broader than you think.

For one culture to have an idea and share it to others isn’t uncommon. Pyramids are in Egypt and Mesoamerica. Giants exist in many cultural myths (see https://en.wikipedia.org/wiki/List_of_giants_in_mythology_and_folklore) as are ghosts (https://en.wikipedia.org/wiki/List_of_ghosts).

You see, an idea that’s communicated is a meme.

" A meme acts as a unit for carrying cultural ideas, symbols, or practices, that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena with a mimicked theme. "

https://en.wikipedia.org/wiki/Meme

If you’re considering spirit as a soul

https://www.planksip.org/the-concept-of-the-soul-in-ancient-philosophy-and-soul-1763067454225/

TL;DR: So, why does it exist across cultures? It’s a meme.