Hello everyone and sorry for the prolonged absence.
I am glad that, all in all, my piece was not disliked.
First of all, I would like to quote Abate, who once again immediately found the problem. In the sense that the piece was indeed closed prematurely. Everything has its reasons, but this one is very prosaic: I no longer had days available, and if I hadn't closed it there, I would have had to publish it whenever.
In truth, the project for the track already had a follow-up, but it would have taken me too far in terms of both duration and the sacrifice required for listening attention, so I preferred to resolve it this way.
As far as relevance to the theme is concerned, I believe the best answer I can give is Zaccaria's: if the theme had been different, the work would have been different.
I believe that everyone has their own methods and codes, and deciphering them is not so simple. In plain words, what I generally do, starting from a given theme, is to subject it to a series of "transformations" (many of which are canonical, many others are not) until I find a path that, to my taste, obviously, best fits the general structure I intend to create, as well as being consistent with my personal style. I wouldn't want to delve into the details of this discussion, otherwise I would end up discussing narrativity, consequentiality, the role of time and mathematics in music, etc., etc., again...
Then, as Frank says, the aesthetic result is what matters most, and it is not guaranteed that a path, even if coherent, will ultimately turn out to be pleasant. If it does, it's all gain.
I forgot, those little harmonic-type symbols on some notes are just escamotages for the playback that I forgot to remove when I printed the score.