Sunsprite is fragrant, a good bloomer, and fairly disease resistant. I also had New Day, it is a tea rose so has more issues but it was prolific, fragrant, and disease resistant.
I live in a humid climate, blackspot appears a few days after rain in the humid weather that follows. The best way to keep it to a minimum is to make sure the roses are spaced so that they get plenty of air circulation. My rose bed is next to my driveway and I have no wall on that side to block the air. I select roses with glossy leaves. Glossy leaves have less problems with black spot and mildew and roses that grow on their own roots are generally more disease resistant than hybrid teas. Prune roses to a vase shape to keep the center open and the roses blooming.
In wet humid weather, you need to have a regular antifungal spray program. I prefer sulfur but it is hard to find wet able sulfur. Milk works, it also acts like leaf shine. I have also used horticultural oil or neem as a preventive as it makes the leaves shed moisture. The problem is that oils can burn plants when the temps get over 80 which is most of the time for me. I have also used a baking soda spray which needs either soap or oil or a sticker to keep it on the leaf.
Lastly, if you use either systemic rose care (lasts six weeks), or Bayer tree and shrub ( lasts about a year), these systemics help prevent pests and disease. I used to use Tree and Shrub, but I want to limit the impact on bees since they are having a hard enough time as it is, I have chosen to use the Systemic Rose care only when it rains every night and I have to prune the roses to make sure it does not bloom during this time so bees do not visit.
Unfortunately, roses are high maintenance. However I do have a couple of roses that are not yellow that I never spray and they grow quite wild.
One is baby blanket, it is a ground cover rose. The other is a red rambler rose. These roses have been bullet proof. I don't spray these with anything and they are not near a light. They are in the back yard with the edibles so they are not sprayed at all.
Happy gardening in Hawaii. Gardens are where people grow.