en.wikipedia.org/wiki/Pope_Alexander_VI

This date is off by about three years.

• Catholic-Hierarchy lists Rodrigo de Borja as appointed Administrator of Valencia on 30 June 1458 and installed on 21 July 1458.
• A history published by the Archdiocese of Valencia likewise says he took possession of the Valencian see on 21 June 1458.

So the article's statement that he inherited the Valencia post in 1455 is incorrect; the evidence places his assumption of that office in 1458.

The statement is too absolute.

• The Real Academia de la Historia says Pedro Luis de Borja, Rodrigo's eldest son, was legitimized by Sixtus IV on 5 November 1481 and recognized again in 1483.
• The same institution's biography of César Borja says he was dispensed from the defect of illegitimacy by a bull of Sixtus IV on 1 October 1480 so he could hold benefices.

Since these steps happened in 1480–1481, they predate Rodrigo Borgia's election as pope in 1492. So it is wrong to say he only legitimized his children after becoming pope.

The article gets the end date of that Jubilee rite wrong.

The Vatican's own liturgical documentation says:

• the Holy Year begun by opening the Holy Door on Christmas Eve 1499;
• the Jubilee continued until the Epiphany of the Lord, 6 January 1501;
• and the rite of closing the Holy Door at St. Peter's for the Jubilee of 1500 was celebrated on 6 January 1501.

So Alexander VI did help institutionalize the Holy Door rite for that Jubilee, but it was not closed on Christmas Day the following year. The official closing was on Epiphany, 6 January 1501.

The documentary record cited by Spanish historical reference works says the dispensation was issued by Pope Sixtus IV, not left to Rodrigo Borgia's personal discretion.

• Historia Hispánica (Real Academia de la Historia) states that on 1 December 1471, Sixtus IV signed the dispensation bull for the marriage of Ferdinand and Isabel and later gave Rodrigo Borja legatine powers to bring it to the Peninsula.
• The Biblioteca Virtual Miguel de Cervantes likewise says the marriage dispensation was granted by Sixtus IV in December 1471, while Rodrigo's legation was a separate step.

So Rodrigo Borgia did play an important diplomatic role, but the claim that the pope gave him discretion to decide whether to grant the dispensation is not accurate: the pope himself issued the bull.