Hmm... last evening I saw several in August. Yep, just checked aagain. I see three 4-night cruises and four 3-night cruises on the Wish in August. I only have 2 adults listed in my party at the moment, if you have more passengers, or any are children, it's possible that's limiting availability for you.
Oops - I just realized you are now asking about September. I don't see any September 2022 cruises available on the Wish. Those must be sold out. I do see 3-night cruises departing each Friday (total of 5). The Wish sailings are very popular because everyone wants to check out the new ship.