Maybe you'll understand that those experiences are very different from each other before you 'die'. One just needs to study the myriads of detailed NDE reports to see that they all lack destinct characteristics of DMT trips (or similar psychedelics for that matter).

Also, there is no proof whatsoever that endogenous DMT even exists. It was merely postulated as a theory by the scientist who conducted the human DMT trials. Many people who read his book misinterpreted that part (read what they wanted to read) and ran with it. He later published an article specifically to clear it up, but it was already too late.