This is assuming that you will be staying at a hotel in Waikiki because there are rules against Airbnbs and it's really hard to get any in Kailua or Waimanlo.
I haven't included when / where to pick up snacks or all the meals as that will be up to you. I love Acai bowls and Pike bowls so I have suggested those every day (that's all I eat when I go) and then use Uber Eats to the hotel at night when you're super tired.
In terms of this trip - I've given you an absolutely packed trip which will be amazing but leave you exhausted. My last few trips to Hawaii have been 1-2 activities a day and mostly relaxing at the beach!