Interesting Johan, thank you.
In Dutch we have quite a number of words and titles. Sometimes they simply give a male or a female version others are used for both men and women,
Ambassador, minister (as in both secretary of state and as reverend), vicar and commissary of the king are positions that keep the same form in Dutch no matter if the one in that position is male or female.
The current king also has appointed women as Kamerheer in some of the provinces. Kamerheer is a title that translates as gentleman of the chamber so it's quite strange to have a woman be a gentleman, i would have preferred another title for the entire group but they did not opt to do so.
In the Dutch language we have a male and a female version for secretary but they mean different things a secretaresse (the female version is the one typing the letters, taking care of the post and schedule of her employer. A secretaris (the male version) is usually someone in a position of control and authority.
In general most professions have a name that has become gender neutral in its use.
The constitution was written at a time when the position of men and women was in no way equal, certainly not in law. So they wrote it with a man as head of state in mind. They even used some elements from 1748 such as the need for permission of the Estates-General for a Royal marriage to be dynastic and the marrying Dutch Royal to keep his or her rights of succession.
The succession was between 1814 and 1885 semi-Salic. So any male line would precede a daughter of the king. Meaning that when princess Wilhelmina was born in 1880 the line of succession was:
1 the Prince of Orange (her half brother Alexander)
2 Prince Frederik of the Netherlands (her father's uncle)
Wilhelmina did not become the heiress to the throne until 1884 when both her great-uncle and her half-brother had died.
Had uncle Fritz outlived his nephew Willem III his line would have continued.
Had the marriages of Willem III's brother prince Hendrik the Sailor produced a son that nephew and not the daughter Wilhelmina would have been heir to the thrones of Willem III/Guillaume III.
When Wilhelmina married a special law had to be made because at that time women who married lost their legal capacity to sign legal documents. A married woman could not sell property she owned before her marriage or she inherited. Her husband could however without needing his wife's consent.
So a marriage of Queen Wilhelmina would have rendered her signature under laws, appointments etc illegal had no special arrangements been made. That is why some wrote of HM King Heinrich and Duchess Wilhelmina. As Heinrich would gain the legal authority to sign in place of his wife and she would take her husband's rank as women usually did in marriage.
The wording of the oath was not really altered and has remained more or less the same since the original version of 1814. Had one of the queens opted to use the word queen instead of king i doubt anyone would have objected. I think we might see Catharina-Amalia do so or potentially use the term monarch as that covers both male and female once it is her time to be sworn in.
I feel sorrow for you, people of limited vocabulary .
We have two words:
Embaixatriz is the Ambassador/ Embaixador 's wife
Embaixadora is the woman who is the ambassador in her own right.
Never would a Queen of Portugal be styled as king
We also say Soberano-Soberana .
The only one gender related name is Monarca