sir

you overlooked the second part

rather than his (ii) ________ genetics, which lacked any distinction,

So we can analyze the first part of the sentence as follow

In the course of a transatlantic voyage following the First World War, he magically acquired an honorific title of “Count” as well as a “von” in his name,

he had the title of count and von. Ok he became important or a VIP person. so far so good

a development due to his aquiline nose


he had those titles because the nose and as such he was regal as a consequence


and social (i) ________??????????????

and social skills = defteness

Now the key part

He was elevated to a noble person for his nose and skills

rather than or despite his peasant genetics which were basic.

In other words, he became someone important regardless of his basic, without skills origins or status

If you insert the word patrician you mean that he received the title of noble despite his heritage of rich which

1) has no sense
2) it is not the meaning of the sentence

I hope this helps