Questions about Multibrackets Table Mount Gas Lift Arm Desk

Good day The specifications state a payload of 21kg. In the manufacturer's video, however, the adjustment of the gas suspension, which ultimately has to hold the weight of the monitor in any position, is given as between 2kg and 10kg. What is correct now?

Hello, will this arm work with the Samsung CHG90 49" monitor and be able to hold the weight? thank you!