Hell? Sheol?

I come from an evangelical Christian background, where heaven and hell are pretty well defined. Heaven is eternal bliss for followers of G-d, and Hell is eternal torment and separation from G-d for those who reject Jesus.

I’m learning more and more about Judaism, and this part is tripping me up. Sheol is some shadowy place? Is it torment? Is it eternal? Is there an opposite of Sheol? If Hell doesn’t exist, why should I care about living holy? I mean, yes, I want to be kind to my fellow humans, of course, but what about the biblical laws and rules which don’t really appear to impact other people?

Can anyone give me direction in this topic? Thank you!