Eunuchs were common thing if that is your point,yes.And i do not deny that.Did I say they were all eunuchs?
To deny that was a common occurrence is silly, however.
"White Eunuchs were Europeans from the Balkans or the Caucasus, either purchased in the slave markets or were boys taken from Christian families in the Balkans who were unable to pay the Jizya tax. They served the recruits at the Palace School and were from 1582 prohibited from entering the Harem."
"The entire Devşirme system, where the children of Christian families in the Balkans unable to pay the onerous jizya tax were taken away, and, depending upon their sex, became either concubines, in the case of the girls, or, in the case of the boys, were conscripted into Janissary Corps or became eunuchs. The act (emasculation) made Ottoman rule much hated by Christians in the Balkans."
https://en.wikipedia.org/wiki/Eunuch#Ottoman_Empire
In the case of Sicily, this is what Chiarelli has to say:
"Thus, this quarter seems to have been named after the white European eunuch slaves who were an important part of the Fatimid army and held high positions in bureaucratic offices of the government. Arabic sources generically referred to these white slave sas "saqalibah" regardless of their actual origins,which vary. They were mostly of Slavic origin, since the name originally meant Slav, that is, those people who inhabited central Europe and the Balkans. It was also used to designate any European originating outside the Frankish and Byzantine empires, although at times it was also used for southern Italians (especially Lombards) and some Sicilians."
P. 255-258
Many rose to great heights as leaders of armies and as civilian administrators.
Whether they were made eunuchs or not seems very much to depend on the place, the dynasty, the rulers etc.
Did you miss these tidbits when you were doing your research?
"In al-Andalus, Slavic eunuchs were so popular and widely distributed that they became synonymous with Saqāliba.[4]"
"Theophanes mentions that the Umayyad caliph Muawiyah I settled a whole army of 5,000 Slavic mercenaries in Syria in the 660s."
You should know by now that I don't make things up.
However Eunuch job was very much different from that of the either soldier or administrator.
You quoted for the Janissaries,they weren't castrated but "forbidden" to marry.Janissaries were initially forbidden from marriage or from having families. However, they were eventually able to lobby the Sultan to have this restriction lifted. Later on, they also successfully lobbied the Sultans to allow their sons to follow them into service.Do you think that Janissaries with such a influence that could even change Sultans and have even killed some of them,were not having any woman?
Eunuchs and Janissaries were not same,much less the administrators.
There were also black eunuchs for example that guarded the Ottoman harem.