I had a shitty childhood, was miserable in my teens, was possibly even more miserable through my 20s. When I was 16 I told myself if I was still as miserable by 30 I would consider ending it there.
Fortunately around 30, after my low point of the pandemic, is where things started to actually fall into place for me - both in terms of external factors and, slowly, internal monologue.
While I still have a lot of mental holdovers from all that time spent in a depressed state, I would generally say I'm sustainably "happy" these days. Something I genuinely thought I would never reach.
To anyone in a bad place right now, just know that if you stick it out, life actually can be surprisingly worthwhile.