Clarification on Jesus

Ok... What was the point of Jesus dying for our sins?

Hear me out: I was told that Jesus died for all of our sins and they're all forgiven.

But: why do people go to hell for not believing? Did he die for almost all of our sins except that one?

That honestly leaves most of humanity out then.

So he died for the sins of a select few, who also have to apologize for their sins and have to try to have a relationship with him and if they don't, they aren't forgiven.

Are they forgiven or not?