Based on your definition, Noname could be considered the most poetic in the literal sense. She uses structures in her music similar to that of a poet, and she also uses plenty of literary devices in her music. a great example of the poetic structure she uses is in her song, "Reality Check".
While the content of his music is vulgar and inappropriate, Eminem is one of the most poetic rappers of all time. He constructs some of the most creative metaphors, and wordplay in general, in all of Hip Hop. His song "Berzerk" is a great example, as there is wordplay present in almost every verse.
Rakim is considered a legend in Hip Hop. His music contains a good blend of wordplay, along with poetic structure and poetic devices. His song, "Mystery(Who Is God)", showcases this blend perfectly.
Kendrick Lamar is considered the best rap artist of this generation. The main aspect of his music that makes him poetic is his storytelling. He is able to tell beautiful stories using incredible wordplay, such as metaphors. One of the best examples of this is in his song called "u".
Aesop Rock has arguably the most expansive vocabulary in Hip Hop. He uses many advanced words in his rhymes and manages to create a rhyme pattern that is pleasant to listen to. One of his best works is his song "Rings", in which he showcases his vast vocabulary and ability to create thought provoking lyrics.