I think the short answer is quite simply nobody really knows.

Your best bet IMO is to ignore genetics (can't change it), pick a "Blue Zone", and emulate what you can- within reason. This is something we still haven't solved, so the next best thing is to try to follow a proven playbook. You could call it cargo cult'ing, but until we crack the code it's the best we've got.

Then you can sprinkle in rock-solid conventional knowledge, for example we're pretty much dead-certain that exercise is good for you and time in nature improves your well-being.