What is that one thing to acquire in life, in order to be satisfied at death bed?

Hmmmm.... Just do whatever you like. Experience everything at least once which is on your list. And love yourself the most

I can only answer for myself. I would be satisfied on death bed if I feel I have done well and achieved satisfactory progress in the so-called goals of life: Dharma, Artha, Kama, Moksha.

I also want to impact thousands (or more if I can..) of lives positively, that would give me satisfaction on death bed.