Question about a sermon in the Gemara

Here is the eighth of the month? It is written: “And sons were born to David in Hebron: and his firstborn was Amnon, by Ahinoam the Jezreelitess. And the second, by Abigail the wife of Nabal the Carmelite; and the third, Absalom the son of Maacah… and the fourth, Adonijah the son of Haggith; and the fifth, Shephatiah the son of Abital. And the son of Shechem shall be a son of Eglah, David’s wife, which were born to David in Hebron. And the prophet said to her: “In a little while, and she shall gather unto thee a priest and a priestess.” “A priest” – Seth, “and a priestess” – Seth, they shall be eighty-two years old. Rabbah says about her: He said, “a priestess” – twenty-two years old, “and a priestess” – twenty-four years old. Tanya Namei Hachi: “He shall not multiply wives for him” – one left over from ten and a quarter. From the number of Dedaresh and Yu, there were forty and eight. Tanya Namei Hachi: “He shall not multiply wives for him” – one left over from forty and eight
I brought up part of a question from the Sanhedrin to ask what you think about sermons. How do you perceive this? Do you think they are really referring to the source of the saying “He shall not multiply wives” in the Sabra? Did the Sages themselves think they were really referring to the source in the Torah? Because on the surface, these seem to be very narrow-minded opinions…
If you have an article then I would be happy.
Thank you very much.