Bit of a divergence, but why not... such is my way.
Ok... so I had generically said sodium bicarbonate, typically known as Baking Soda, because I often use buttermilk in my batters... sometimes yogurt. These are chemical leavens in their own right, and as they are quite acidic, using Baking Powder as the sole leavening agent can leave behind a chemical-like finish on the palette as the chemical reaction in efforts to induce CO2 production will be incomplete... or rather will leave behind acid salts. Monocalcium Phosphate, typically known as Baking Powder (also has a little sodium bicarbonate mixed in), is what your recipe called for apparently, and that you find your waffle to not be as sweet as you'd like might be because of the science I'm explaining. For shits & giggles, try this. Split your baking powder dose in half, and then add 50% of that as soda (e.g., 2T powder becomes 1T powder + 1/2T soda). I recommend this ratio anytime you are working with acidic batters.
Have you tasted Dragon Fruit? I find it quite bland. Yeah... a little Kiwi, a little apple/pear, but a very delicate footprint, for sure. It's worth trying alone as it is so delicate, but a little help might not be a bad idea. Maybe just that... a little kiwi.. a little apple. Maybe an aromatic herb... fresh tarragon is screaming at me. I have found the interestingly crisp yet supple texture works AWESOME in concert with Granita. Here's a simple Blood Orange Granita on Dragonfruit.
The icy grains sort of disperse in the dragon fruit as you masticate... it's really interesting. Granita is another good prospect to use the Dragonfruit... there is a synergy with the texture.