I also grew my pink Dragon Fruit for many years before it produced.
They like to be fertilized and they love water.
yes I know they are a cactus...
but if you want fruit you need to water 'well' during their growth period.
They need to climb, but not too high. You do need to reach them for picking.
For me they only make fruit on the branches that are HANGING DOWN.
My trellis is an 8 foot tall tripod with cross beams 2 feet below the top.
Happy gardening.
