Does 莫過於 require 最 for first noun?
In theory, we don't need 最 in '痛苦莫過於生存' because 莫過於 (no greater than) already indicated 'the most'.
However, &quot;最X 的Y 莫過於Z&quot; is a common structure of speech. For example 最危險的任務 莫過於 卧底行動  (the most dangerous task is the undercover operation/ no operation is more dangerous than an undercover operation)

最 emphasizes the topic

莫過於 emphasizes the object in the comment (or you can simply say 最危險的任務是卧底行動)


I don't agree with this statement. Life itself is neutral. It can be full of happiness or sadness, and the way 鄭詩君 said it is not quite the standard way