reversing aging is not the same as immortality. you might be making a comparison that doesn't make sense.

there's a well trod phrase:

The word "aging" is sometimes used to refer to the total system failure that comes with age. And so when people say "reverse aging," they often mean reversing total system failure. It might be the case though that we are able to reverse some systems and thus reverse some parts of aging, but that other systems are more complex than we give them credit for or could possibly appreciate.

All that is to say that I think immortality is within our reach. That it is a surmountable engineering problem.

However, it may not be within my reach. I'm also not certain after some decades of being a life extension enthusiast, whether or not I still hold the view that living indefinitely is the superior option.