You luckily have an abbreviation in your DNA that means your tellemeres don't shorten. You can't age. You reach 87000 years old. Humans have gone extinct. You are trapped alone on a dead earth. You try to shoot yourself but the gun misfires. You jump off w cliff, but a sudden updraft catches you and you land safely. In this multiverse, luck is now objective.
I luckily found a way to end myself in that scenario or I luckily never experienced that in the first place and had a wonderful life. Luck very subjective to the person that's why there's no drawbacks to it
Good point, if you're 100% subjectively lucky, not only you would have that 'live-forever DNA' but also everyone else that you'd wish for, i.e. all your loved ones. And if you were looking for a new friend or partner, you'd always find a perfect match immediately.
I guess such an ability might have severe negative consequences for the part of the universe you dislike or don't care about. But from a purely egocentric point of view, I can't see any drawbacks at the moment.
Luck is not an infinite resource, meaning that when ever you get lucky, somebody else won't. So you'll actively will siphon luck from people around you. Good luck with the loneliness, no pun intended