The Brief: The phrase "unalive myself/yourself" refers to an individual dying by suicide.

DEEP DIVE
To “unalive myself/yourself” is to refer to an individual taking their own life.
Unalive refers to no longer living or being alive. It is often used as a joke on social media. However, the phrase is also used in lieu of saying “died by suicide” or committed suicide.”
If you or someone you know is struggling with suicidal thoughts please call the National Suicide Prevention Lifeline (Lifeline) at 1-800-273-TALK (8255), or text the Crisis Text Line (text HELLO to 741741).
My urge to be a milf is stronger than my urge to unalive myself and I think that’s beautiful
— certified hater (@pairating) April 27, 2021
i accidentally flashed some semi truck drivers today. but they gave me 2 thumbs up so i feel better i won’t unalive myself today
— 🦇 (@ciercx) April 27, 2021