If you want to mean that you would like to have something important in your life that would be a reason to live, I would say: "Desearía/quisiera tener algo por lo que vivir".

I think that you mean you wish you could experience something difficult or challenging in your life, and overcome it, survive it, and move on with your life. If this is what you mean, I would say it like this: "Me gustaría vivir una experiencia difícil en mi vida, y ser capaz de superarla." If you wanted to go a bit more extreme, you could say: "Desearía vivir un reto muy difícil en mi vida, y sobrevivir (survive)." Buena suerte!

I would say: "Quisiera poder superar algo"

Desearía poder vivir algo