I don't think you're delusional. No one knows for sure what comes after death, if anything. Anyone who says they know 100% for certain is lying.
Personally, I think it's a state of non-existence; the same as before you were born. Billions of people have died before us and no one has come back from the other side. What came before is what will come after.
I don't know this absolutely but I'm pretty confident that's the case, and it's my personal belief.
I think NDEs and experiences had under the influence of psychedelics are most likely powerful creations of the mind. But the study of these things have just barely begun, there's plenty we don't know.
There could be non-existence, an afterlife, reincarnation, etc.