I think it's important to remember your fate as it is right now.

If you manage to survive car accidents, violence, early cancer, genetic disease, or spontaneous cardiac death, your best case scenario is you go to be drugged until death in a hospice, or receive an amateur attempt at medical care by cryonics.  (what makes it amateur is that as no one has revived a human brain sample and validated the cells function again, this missing feedback likely means each cryonics process makes dozens of fatal mistakes and the best that can be done is a computer emulation of the deceased individual).

If you're this lucky, your children will be noticeably decayed by aging from their peak when they visit you on your deathbed.  They will be uglier, dumber, weaker, and have nothing to look forward to but your fate.  And the same for your grandchildren, if any are alive at this point, and so on.  

If AI fails or is paused, you can think that "well at least humanity will continue" but you won't at all know that, all you know is you didn't live to see the Doom.  

So a wildcard like AI makes new things possible.  While we humans don't know precisely how to solve aging, it's possible and experimentally seems to be viable.  Rats still die, so at age 130+ there are probably thousands of possible ways a rejuvenated body would begin to fail, and so you need some way to know what the treatment is for almost all cases.  Human minds are likely not capable of managing this amount of complexity.  But it's possible, nature makes new bodies 385,000 times a day via an unintelligent automated process.  

Some machine could review all of the papers on medicine, and all of the patients records available on earth, and then design and run likely billions of individual experiments at varying scales to resolve ambiguities, and then model human biology precisely enough to intervene and keep a patient alive across almost all cases.

Interesting times bring opportunity.  You were definitely going to lose the game before recent breakthroughs, now you might lose.  

I don’t trust that the replacements will be actually good

If ∑(people who agree with you on this * how much they agree with you) is high enough, that constitutes market demand for making an actually good replacement, or remaking the original.  Then the cost-benefit calculation determines whether the market will incentivize someone (or an AI) to solve the problem.

If you, personally, have preferences that are truly unusual, then that could be a problem.  Though I do expect the technology to make individually customized solutions cheaper and more feasible (in the vein of 3D printing).  Perhaps, among all the truly unusual preferences you have, the net move will be towards more satisfaction of them.

I’m not going to say I don’t share deep disquiet about where AI is taking us, setting aside existential risk. One thing that gives me hope, however, is seeing what has happened in chess. The doom mongers might have predicted, with the advent of StockFish and AlphaZero, that human interest in chess would greatly diminish, because, after all, what is the point when the machines are so much better than the world champion ( world champion ELO ~2800, StockFish ELO ~4000) . But this hasn’t happened, chess is thriving and the games of the best human players are widely streamed and analysed and their brilliancies greatly admired. The machines have actually been of great benefit. They have, for instance demonstrated that the classical swashbuckling 19th century style of chess, replete with strategic sacrifices that lead to beautiful attacks, is a valid way to play, because they often play that way themselves. This style of play was for a long period overshadowed by a preference for the more stifling positional chess, the gaining of small advantages.  The machines also provide instant feedback in analysis on what is ground truth, whether a particular move is good, bad or neutral. This too has augmented the chess players enjoyment of the game rather than reduced It.

  Maybe we can hope that the same situation will apply in other fields of human endeavour.