In Carella City, ageing can be postponed but not vanquished, until an exiled murderer helps a 157 year old woman evade her creator.

It sounds like you've focused more on developing the special scifi elements than the hero himself.
What is the meaning of your story? What's the take away message that's revealed in your hero's actions?

From what I am reading, what's missing are the stakes.

It isn't coming across in your logline, nor in your brief synopsis?why living longer and aging slower is a bad thing.

What makes aging naturally the correct choice and worth fighting for? What makes a slower aging process bad enough it is worth fighting against?

I only say this because aging naturally vs aging using nanotechnology seems to be the dramatic question of your story.

Yeah, I've been trying to condense it too much I feel.

In a vain future world, Carella Corp offer a 'Nanolife' technology allowing ageing to be postponed. Karl's job is to dispose of people when the Nanolife runs out. He meets a 157 year old woman, Penelope, who has escaped from Carella Corp, who claims she has advanced Nano technology. Karl falls for her and helps her escape from Carella Corp who are searching for her. When they eventually catch up to the pair, Penelope sacrifices herself to protect Karl. Karl later finds a society of humans living free from Nano technology, ageing naturally.? After learning that he was blackmailed into his previous job, for his daughter's safety by Carella Corp, they help him break in to the City, to rescue her. Karl is captured by Carella Corp and told the truth, that he was setup by them and Penelope is actually AI, with false implanted memories designed to test out the latest version of Nano technology. They are broken free by helpers and set about releasing thousands of those enslaved by Carella Corp.