Airport exchange desks are expensive for structural reasons: high rents, captive customers who need cash right now, and no meaningful competition inside the terminal. The cost hides in two places, an unfavorable exchange rate margin and sometimes an added fee on top, so even a desk advertising no commission can quietly take a substantial cut through the rate.
Better options: withdraw from an ATM at the airport instead, ideally one operated by an actual bank rather than an independent convenience machine, using a home card with low foreign fees. Or exchange just enough for the taxi and first meal, then use banks or established exchange offices in the city, which live off repeat customers and competitive rates.
Two cautions wherever you exchange or withdraw: decline any offer to be charged in your home currency, since that conversion is always worse, and be wary of standalone ATMs in tourist zones with steep operator fees. Comparing the final amount you'll receive, not the posted rate, is the only honest comparison.