If you want Aulani and the Sep use year (which seems harder to find), I would not back out. While theoretically if the contract was not partially stripped you could have rented the points out at $20, that's really neither here nor there. First, you are not really giving up $20/point because you are not paying the dues on the used points whereas if you had those points you would have likely paid the dues and the (hypothetical) rental profit would be close to $10/point rather than $20/point. Second, you're not really buying this to be in the business of renting points. Third, this is hardly a "stripped contract"; a fully stripped contract would have zero 2023 and zero 2024 points. And lastly, it doesn't even sound like you need points before next Fall and by the time this closes you can book what you need inside the 11 month window.
Since I'm not paying dues on stripped points and rarely need points immediately (so it's not like I have to rent from someone else) I tend to view the "stripping" more as a loss of a use year. For a 40 year contract, 1 year is not a big deal. It'd be a bigger deal if this was a 2042 resort like BCV or BWV, but Aulani is a 2062 resort.
IMO, the "big decision" with Aulani is do you pay more for subsidized dues or less for the standard dues. Over the next 40 years, the main expense you will have are the annual dues, not the upfront cost. Excluding a couple of 2042 resorts (HHI and VB), Aulani already has the highest dues in the system. So is it worth paying $30, $40, or $50 more upfront per point (and presumably be able to also sell for a premium if you don't keep it to 2062) in order to go from virtually the highest dues in the
DVC system to the lowest dues in the DVC system? This is a highly debatable topic that owners here highly differ on. The only reason I would cancel your the genuinely "steal" of a deal you got is if you decide to go the subsidized route because you won't be able to stomach the $12/point, $15/point, and $20+/point dues that Aulani will eventually see in the years and decades to come (if dues grow at 3.5% a year, they double in about 20 years).