Is it true that the word "Shaykh" is not used for a memorizer of the Qur’an or for teachers of the Qur’an, but rather is used for "your jurist in religion and your elder in age"?

There is no objection to saying "O Sheikh" to a memorizer of the Quran, as there is no legal impediment, and because the word is used for people of status and importance, and a memorizer of the Quran is most deserving of that. Allah Almighty said: "Then We caused to inherit the Book those We have chosen of Our servants" (Quran 35:32), and in the Hadith: "Indeed, Allah raises some people by this Book and lowers others by it."