The Jedi religion has been at the heart of Star Wars since A New Hope’s release in 1977. Unlike the Sith, the Jedi were plentiful before Order 66. While the Sith pride themselves on competing with one another, Jedi strive to cooperate with those around them. The Jedi Code—which defines a Jedi’s beliefs—has constantly been modified and adapted over time. There’s no doubt characters like Master Yoda helped shape the Jedi Code into what audiences see in the prequel trilogy. It is this Code that specifies a Master may take only one apprentice, and it is the Code that forbids romantic relationships.
Given how the original Jedi Code changed and evolved in each era of the galaxy far, far away, Rey’s New Jedi Order could easily create new Jedi ranks. In Star Wars Legends, there were different paths a Jedi could take, such as the role of Jedi Consular, Jedi Guardian, or Jedi Sentinel. And while these classifications still exist in canon, they are viewed more like professions than actual ranks. The Star Wars Book from 2020—featuring contributions from Pablo Hidalgo, Dan Zehr, and Cole Horton—outlines the six official ranks of the Jedi Order. These ranks are described as the "Jedi Path," and dictate the single route of advancement in the Order.
