If you go to https://ifconfig.me/lang do you see ONLY zh-CN but you never selected Chinese in your browser? I've noticed some that visit from here have that as their "only" language which is a sign of a possible browser hijacking application or extension, or a number of people only speak Chinese which would be kindof cool, or something else entirely benign but I am curious which is happening. A lack of zh-CH does not mean a node is not hijacked, just the ones with really lazy sloppy code.
What sent me down this path was one of the botters here on HN sending me playful messages from residential/mobile agents they have control over. A friendly taunt. The game is afoot.