The use of "superlatives of superlatives" is a literary device to denote the highest order of something.
It is akin to how the word Meta is used in the Lionsberg System.
For instance, when describing One / God superlatives of superlatives such as "King of Kings", "Lord of Lords", etc. are often used.
In the Lionsberg System we might instead say "the Meta King" or the "Meta Lord".
These various devices are just Word Tools. It is what they point to that is important.