Although knighthood was still mentioned in the Kosice privilege of 1374, granted by the Polish king Louis, known as the Hungarian, it was already the period of creating the nobility democracy, somehow following the Athenian model, as this privilege simultaneously imposed the obligation of military service on knights - the nobility. And so the amateur army which grew out of Casimir the Restorer's reforms in the 11th century, from which the "knightly profession" arose, 300 years later already became a social status, privileged, but also obliged to fight for the country.
Certainly Louis of Hungary must have had a vision of the nobility following the Western model, after all his mother descended from the Polish Piasts, but his father from the French Capetines, i.e. the rulers of that part of Europe where the nobility had existed for a long time, as a certain hereditary privilege, a state to which one belonged by birth and nothing else was required, it was like a "state of nature". In these countries, the power of the king or prince did not come from the election of a multitude of subjects, but from birth.
And furthermore, the state was not numerous, its character was as if more courtly or clerical, largely consisting of people serving their boss, lord and ruler, where no demands on the ruler came into play. It was the boss who told the "staff" how things should be, not the staff to the boss. Besides, the "boss" could easily cope with the opposition of the "staff", not very numerous, with the help of his guard or police force, recruited mainly from people outside this privileged state.
However, the Polish knighthood, or nobility as it will be from now on, forced certain restrictions on the king's power, thus somewhat differently than in Western Europe. This forcing was actually a political arrangement, the king needed knights for a fight which he would not be able to wage without the consent of the Polish knighthood, so a theoretically amateur army, not a professional one. And there was not enough professional army to win wars. And the "band of knights", later the nobility, was very numerous in Poland, ten, twenty or thirty times more numerous than in Western Europe, after all according to the assumption of the Kazimierz reforms it was to be an essential part of the military forces, not the "chief's staff". This was a force the king had to reckon with.
The Kosice Privilege would probably be more correct to call it the Kosice Agreement: it imposed the duty to defend the country (but not war expeditions to other countries), but also the duty of the king to buy out the knights from slavery, plus no taxes without the consent of the knights, plus offices only for Poles. This agreement was the price Ludwig had to pay for the rights to the Polish crown. The nobility in Poland developed not as a group of courtiers or clerks vying for the favour of their lord and master, but as a military group whose requirements the king would either meet or... get off the throne.
Well, maybe not - once the throne had been given away, the ruler stayed on it, but to get on the throne required the consent of this "band of nobles". However, since the agreement was made, the ruler could rely on it, because the "Polish band of nobles" had their honour and kept the agreement.
Some describe it as an advantage, others as a disadvantage of the Polish system. When a new ruler wanted to get on the throne of Poland, he praised the democracy, but when he got on, he found it disturbing. Voters, in turn, praised the privilege of being elected, but when the ruler intended to actually do something by forcing the voters, he met with resistance. And so on and so forth. There was, however, an advantage to this system: each voter, for better or worse, supplied the army at his own expense, which showed its merit, especially when there were able chiefs. And it was these chieftains who were perhaps the most valued group of leaders in Poland, and the king-chief was that ideal king.
And these chieftains and the king-chieftain were exalted by the "nobility" as if by nature, a chieftain is a chieftain, while the rest of the nobility recognized that there is no other reason for one to exalt himself above the other, that all are equal, even if someone holds a more important office, still "a nobleman on the farm is equal to the governor".
(Translated with www.DeepL.com/Translator)