Shamans know the truth because leaving the body is a daily activity for them.
After death, there will be something different from what religion preaches.
Karma is absolutely real – the universe is an intelligent organism: after death, a person will experience what they have caused to others.
A large part of people go to heaven or hell after death: heavens and hells were created by people themselves by the power of their faith: people are powerful beings – they are creators, and if many people believe in it, if it is really created: it is a fictional reality created by people. After a certain time, in heavens and hells, people are attended by beings who try to pull them out of this illusion and move them higher to knowledge into the inter-incarnation period where people re-evaluate their lives and prepare for the next incarnation.
A person who has done a lot of evil will fall into the hellish worlds – temporarily – but it is a completely different hell than religious ideas.
A materialistic person will be slightly disoriented after death: they will find themselves in the world of their youth. This person has created this world themselves and considers it real. Later, beings come and awaken this person from this illusion, moving them higher towards knowledge in higher dimensions.
In the next life, the oppressor will be reincarnated into the role of the victim – karma really exists.