en.wikipedia.org/wiki/Sublimation_(psychology)

Available descriptions of The Harz Journey identify it as Heinrich Heine’s account of his own 1824 journey through the Harz Mountains. A modern edition summary describes it as Heine’s “description of the journey” and says Heine “hiked through the Harz Mountains” before publishing the work in 1826.

That directly conflicts with calling the work “a story ... about Johann Friedrich Dieffenbach.” The Dieffenbach material is an anecdote, not the subject of The Harz Journey.

There is also a second factual problem in the sentence: the anecdote Heine is quoted as telling places the tail-cutting when he and Dieffenbach were students at Bonn, not in Dieffenbach’s childhood. One source quoting Heine gives: “my university friend, Dreffenbach, when we were students at Bonn, used to cut off the tails of dogs and cats...” So the article’s wording shifts the timing from student years to childhood.

Because both the subject of the work and the timing of the anecdote are misstated, this sentence is inaccurate.

This misstates what Aschenbach writes in Death in Venice.

In the text itself, Aschenbach is introduced as the author of prose works, including a “prose epic” and a treatise. Later, when his desire for Tadzio briefly renews his creativity, Mann says he produces “a page and a half of choice prose.” Other reliable summaries of the novella likewise describe this as an essay or say that his writer’s block lifts and he writes again; they do not describe him as turning the desire into poetry.

So the psychoanalytic interpretation may be arguable, but the concrete literary claim here is wrong on the text: the work produced is presented as prose/essay writing, not poetry.