Is the story of the incestuous killer in the time of Prophet Yahya, as mentioned by Ibn Kathir, correct?

It is mentioned that the reason for the killing of John (Yahya), peace be upon him, was his refusal of the king of Damascus's marriage to one of his maharim (unmarriageable kin), which angered the woman. So, she asked the king for John's head.

These narratives, even if reported by some Companions like Ibn Abbas, are most likely taken from the People of the Book.

The jurisprudential rule regarding Isra'iliyat (narratives from Jewish or Christian sources) whose truth or falsehood has not been confirmed by revelation is neither to affirm nor deny them, in accordance with the Prophet's saying, peace and blessings be upon him: "Do not believe the People of the Book nor disbelieve them, but say: 'We believe in Allah and what has been revealed to us.'"

Therefore, there is no harm in narrating this story without asserting its truth or falsehood.