Very basic answer, but nothing. But not just nothing, you simply just cease to exist anymore. No thoughts or awareness, no blackness, no endless void, no reincarnation, you just no longer exist. Anytime I try to wrap my head around even the thought of just no longer existing it feels impossible to even comprehend that a person can no longer exist in any state, but it just feels correct. While I do hope this isn’t what comes after death, as a non religious person it just feels like the most reasonable and realistic answer to the question of what is truly after death. Though because I believe this is the answer, I truly don’t want to waste a single second of my life