While this decision should really be up to you, and all that you need to ensure is that you're consistent in using the same name, I'll share an anecdote, which might give you a different perspective on long names.
There was a researcher who, presumably from a similar culture/country as you, had a long name, which for the sake of anonymity, I'll call L. Ipsum Dolór de Sit Amét. In many journals, the rule for truncating multiple authors to et al. is (if using author names in citations, instead of numbers):
- 2 authors — explicitly name both
- 3 authors or more — explicitly name first and truncate the rest
(Some publishers name all authors if up to 3 total and name 2 and truncate the rest if 4 or more, etc., but the general idea remains the same)
Now someone I knew, had to cite a few papers of Dr. Ipsum Dolór de Sit Amét. Although the primary papers were by "J. SingleLongName and L. Ipsum Dolór de Sit Amét" and "L. Ipsum Dolór de Sit Amét and P. SomeoneElse", there was a closely related followup/auxiliary paper written by "P. SomeoneElse, L. Ipsum Dolór de Sit Amét and J. SingleLongName" which also briefly touches upon (as a background) the material in the other two and cite them.
Now this person was in a dilemma. Referring to the first two explicitly where ever they needed to, took up about three-four lines in a two column journal paper, leading to repeated breaks in the flow of reading. On the other hand, "SomeoneElse et al." was short, memorable and saved space and also contained the relevant idea being referenced to. So in the end, the person chose to cite all three once in the introduction, and use "SomeoneElse et al." everywhere else in the article (effectively making it seem more important than it is). You'd be surprised, but this is not an uncommon occurrence at all.
Now there are different ways to look at it — some might say it was unethical (extreme) or unfair to not cite the canonical article just because of the length of their name. Some might say that while they probably wouldn't do it, there is no real harm™ done, because regardless of the number of times it is mentioned in the body, it appears only once in the list of references and the web spiders will pick it up correctly. Few more might say that it doesn't matter since it's the same set of authors and if you drill down, it is obvious which is the canonical reference. Well, I'm not here to argue for or against any of that. But I will point out that a big impact of someone doing this is that your name loses visibility (not an issue in journals that use numbers for references) and people will only remember it as "SomeoneElse" and a bunch of others. Perhaps you're a special cookie that remembers all 5 authors of every paper, but I don't and many others I know don't.
So if this is a concern, you can use it in full, but abbreviate it to a short one. For instance, use Jorge Fernández de Cossío Díaz in the author list under the title, but in the "cite as" section, use J. F. C. Díaz or J. F-C. Díaz.