Timeshares are designed to be filled year-round, with rooms booked on a first-come, first-served basis. You're less than 4 months out from the second cheapest time of the year, trying to book the cheapest room type (studio). Unfortunately this is not surprising.
Go on the waiting list. SSR, OKW or AKV would have the greatest odds for success. You can have 2 active searches at once. You could also keep checking the website regularly for other options. Depending upon how heavily you travel, a split stay is something to consider. If nothing else, it allows you to enjoy the theming and amenities of two different locations during a single visit. Plus you have a lot better odds of getting 2-3 nights grouped together at different resorts than 5 nights at one.