steep hill, mountain in Hubei
峴 centers on a steep hill or a specific mountain in Hubei. The meaning is primarily geographic, referring to a sharply rising landform.
峴 combines 山 (mountain) with 見, which likely contributes the sound. The character is used for a specific mountain name and steep hills.
A mountain (山) that you can see (見) rising steeply before you: 峴 is a steep hill.
For ケン, imagine Ken (a person) climbing the steep hill: Ken -> ケン, and he's struggling up the slope.