The full sentence is:
I express unqualified awe at Nathaniel.
Be/stand in awe of somebody/something is an idiomatic expression whose meaning is quite close to the concept you want to express. The fixed phrase is in awe of:
- to admire someone or something and be slightly frightened of them/it
- While Diana was in awe of her grandfather, she adored her grandmother.
(Oxford Learner's Dictionary)
The preposition at, used with in awe can be found in sentences like the following where it refers to the preceding verb or expression:
they gazed in awe at the president.
I simply looked on in awe at the remains of what I had just enjoyed.
This ngram shows the usage in published works from Google Books.
You can click on the links at the bottom of that page to see the actual texts--notice that punctuation is ignored in the search results.
In your context I prefer: "My main purpose is to express, from afar, unqualified awe of my leader, Nathaniel."
I don't think you can express awe at someone like some kind of fluid. (apologies for the possible mental image)