So far as the cross, it’s a throwback to a more barbaric time, the idea that we suffer because god requires blood and pain and death for our sins. A primitive rationalization for the existence of disease and natural disasters and drought etc before we could get better explanations. This is very clear in scripture, if it doesn’t rain and your crops die it’s because god is punishing you, if it rains too much it’s because god is punishing you more.
We know now that these things have zero correlation to religious adherence and that they occur because of the chemical and physical properties of the chemical elements, gravity, barometric pressure and various other forces.
Because of this notion that god requires us to suffer in order to be appeased and that that is why disease etc happens, during the middle ages when the plague was decimating the population priests would torture and mutilate themselves in the noble but misguided effort to maximize their own suffering and bring the end of the plague upon us sooner.
It’s a really demented idea and a really monstrous concept of god, one which neither of us subscribes to I’d wager.
But 2,000+ years ago everyone did, and they tried to get out of their own suffering by mystically piling the sins of their tribe on an animal and then destroying it to destroy their sins and bring an end to the foul weather or sickness or whatever that they were experiencing, or prevent it. Then along came the christian religion, which is based on the notion that this vindictive god who can only be satisfied with blood decided to spare us by letting us torture his son to death in our place, and that somehow this sacrifice appeased god so much that we no longer had to do animal sacrifice.
The idea of a savior or a god sacrificing themselves for man is not uncommon. In greek mythology prometheus defies zeus, father of the gods and steals fire from the gods and gives it to man to protect them, because his brother epimetheus gave away the good traits, like fur to stay warm, claws, speed, flight etc to the animals and left nothing for humans. Prometheus was punished for this by being chained to a bolder on the top of a mountain in the blistering sun to have his liver pecked out by a giant bird every day, and it regenerate every night forever. The story of pandora’s box is almost the exact same story as the story of eve and her apple. By some versions pandora was even the first human created by zeus.
This stuff is just mythology. It didn’t actually happen.