You know how they say if you die in a dream you die for real?
I have had multiple extremely vivid, completely realistic dreams wherein I’ve died, only to wake some time after the blackout.
I’m not convinced those were dreams. Either reality reset or I shifted into another one where I didn’t die.
Quantum immortality kinda sucks, actually. Also, reading Recursion by Blake Crouch did actual psychological damage to me, because of how closely the subject matter mirrored my lived experience.
Assuming quantum immortality is anything other than a joke, presumably a cure for aging is discovered sometime in your life.
You should also consider a solipsistic outlook, i.e., you are in fact the only thinking entity that exists, and the rest of the world that you perceive is purely a hallucination. Also, it’s possible that you only came into existence at this very moment and have hallucinated all of your memories before this point.
All that you can know are that you are conscious in this moment, the future does not exist, and the past is indistinguishable from a dream. You perceive the world through your senses, which can be easily tricked or fabricated even by your own mind.