other way around. i surf with a 6.0 x 20.5 x 2.5 fish and its considered chubby for its size/shape. Kite surfboard should be thicker/stronger(more glass)/(heavier) in general to take impacts. I sold a 6.1 x 19.5 x 2.25 last week because every time i rode on it, i'd dent it. Better to cash out while i could.
i'm gonna have to spend the

for a strong EPS board that will last. Was even considering a short fat fish and glassing the top to myself to make the deck stronger. That's usually the weak point of a surfboard for kiting. The deck vs your feet/heel.
think about this. A shortboard is meant to be ridden for a few years, an average of like 10seconds per ride if you're a good surfer not taking into account sun/degradation/water damage. Just one kite session will probably put the use time, plus jumping on it

idk seems like kitesurfboard have to be purpose built. fyi, i've never bought a kite specific board which probably explains why i've damaged my surfboards.