https://developer.roblox.com/en-us/api-reference/property/Player/DevTouchMovementMode
https://developer.roblox.com/en-us/api-reference/property/Player/DevComputerMovementMode
In other words, LocalScripts setting a Server-sided property isn’t possible via normal means. The example documentation should be corrected. This misdocumentation is also shown on other pages related to camera and movement set by the developer (Player.Dev________________Mode).