"In the beginning was the LOGOS, and the LOGOS was with God, and the LOGOS was God."
The dispute amongst theologians is basically summarized dealing with the authority of Jesus and his relationship to God.
One definition of LOGOS is word which legitimizes Jesus as the word of God. But when you look up the word logos in a lexicon you will find many different definitions. A lot of them or dealing with word or discourse however there are some that say the divine/universal principle of reason. There is a Note at the end of the definition citing a reference of the first known use of the word LOGOS G3056 by Heraclitus in the 6th century BCE and I will note that other philosophers used the term in the context 500+ years before John.
Saint John is said to have preached this Gospel in Ephesus (an Ionian Greek colony in Asia Minor) which has Greek roots. One great monument here was The Library of Celsus built by the Romans in the 1st century BCE. Aristotle’s work 2 centuries before this would have been prominent at this library.
Aristotle has a work called Rhetoric in which he outlines the 3 appeals when trying to persuade someone in a argument. Those 3 appeals make up the rhetorical triangle. Aristotle systematically changed the use of the word LOGOS to make it mean Reasoned Word to go with an argument. The 3 appeals are Ethos, Pathos, Logos.