Sorry to hear you’re not finding the availability for Hawaii that you want on II. The hotel exchange is definitely a bit of an anomaly. I‘ve done a couple of searches for II hotels for upcoming trips in 2023 and later, and finding the hotel you want is kind of hit or miss. Unlike the Concierge Collection where you were kind of guaranteed availability (IMO), with II it seems that once the posting is gone (booked by someone) it may not come back. Also, when you search for hotels, change the number of points in the slider. The default seems to be 20, but if you put in a higher amount (100 or higher depending on how ritzy the hotel is) you see that the OOP cost goes down or to zero.
My recommendation for searching II for Hawaii is to search on any location for a timeframe of about a month that includes the dates of your trip. Once the search results are listed, look to see if Hawaii is listed under the US and look to see which dates are available for each resort. When you search this way, you’re looking at weekly rentals. You can decide how many days of the weekly rent to use. On II, it appears that searching for stays of 6 days or less typically doesn’t reveal much inventory. Hawaii postings go very quickly, so if you see it book it.
If you‘re able to get nights on another island, you can book round trip flights on Hawaiian Airlines for pretty cheap, typically about $86 one way. Unless you plan on going to Kauai where there are less nonstop flights, you can easily get back to HNL for your flight out. There are also some of the timeshares on the islands that you can book online. If you’re considering paying for a getaway, you may also want to consider just booking a hotel and paying OOP. Good luck!