An expensive solution. Dragonfruits for me are some of my lowest effort plants and get the least expensive and least time intensive solutions - just gobs of slow release fertilizer and chicken manure.
If you're really set on liquid, you can use pretty much any of them, but I would choose the cheapest possible like General Hydroponics. I have tried tons of fertilizers for indoor plants of uh, various types, and there is very little difference in the end product.
The issue with liquid fertilizer is in fact you're just paying for water and the shipping thereof.