>>16758072
Aging isn't just your DNA, it's damage done to your cells and their proteins and organeles. It comes from a variety of factors, and some of this damage simply cannot be fixed. Also mitochondrial DNA is a lot more responsible for aging than nuclear DNA

You can't just "gene therapy" away something like this. I mean, you literally can't do it at all with modern biotechnology, and with sci-fi magic biotech it's a tossup how much you can change without becoming another species entirely.

As OP correctly pointed out, aging is highly variable between species. This means that "fixing" aging is entirely within the capabilities of biology/evolution, but there are associated benefits and drawbacks that lead to different organisms optimizing for different niches.

Even if we had a magic "aging vaccine" that optimizes your DNA so that you stop aging, we can't even guess what side effects the required changes would have on our metabolism. Maybe you'd need to sleep 18 hours a day, or keep your skin moisturized at all times, or breathe 5% oxygen air only.