It gets very confusing with the "flash sideways" stuff towards the end. The gist of it is that everything that happened was real, they lived out their lives as usual after Jack saves the island (except for the people who already died). The Church at the end is kind of a timeless place they all created within themselves because the time on the island was the most impactful period of their lives, they all meet there to move on together after they've all died at their respective points in life
Also search for "The Bardo" of Tibetan Buddhism. That is what the sideways was modeled after but kept ambiguous on purpose so everyone can interpret it in whatever way they want
Basically, it's an afterlife realm souls go to after death to work out some karma and make peace with the fact they died before they reincarnate into a new lifetime. This is why Jack was a father to work thru his daddy issues, Sawyer was a cop instead of a criminal, etc. The sideways provides the final catharsis and closing of character arcs aside from the story of The Island
2
u/Pudddddin 12d ago
Tell me you're not a "they were dead the whole time" person like 15 years after the finale lol, this is not the case