Lots to see and do right in the Waikiki area that you can get by without a car and make use of the odd Uber/Lyft if you really need to save a bit of walking.
If car rental rates aren't too nuts, still recommend renting a Jeep for even just one day to do a rip around Oahu... sunny day, take off the tops, enjoy the ride, stop for a few spontaneous toe dips, photo ops, eats along the way. Dang, this vicarious posting thing is almost a vacation in and of itself :)
On our last trip we had good luck/value with an Airbnb at the Ilikai in Waikiki. Are quite a few listings in the building. Close to the beach and right next door to the Lagoon at the Hilton. Just make sure you screen the reviews decently to make sure you'd getting a place and host with decent reputation, but that goes for anywhere!
For the second half of our last trip we booked a place on the opposite side of the island just to mix in a slower, quieter more rural feel with the hustle and bustle of Waikiki. Would re-book the identical trip in a heartbeat.
If cost wasnt an issue I think we might try at least a few nights at the Disney resort area. Last memory of the island was a day-trip before heading to the airport for the flight home and it was just enough to leave a guy wanting more. With travel firing up quite a bit these days I'm afraid to even look into what a place costs right now :)
Enjoy!