Jezebel did not enter Ahab's palace as decoration. Tanna DeBei Eliyahu Rabbah 9:1 gives her one sentence, and the sentence is enough to explain a kingdom's collapse.
She was the daughter of Etbaal, king of the Sidonians, and she became the wife of Ahab, king of Israel. The marriage was political. The danger was spiritual. The moment she was brought before Ahab, she taught him the ways of idol worshippers. She did not merely bring foreign luxury into the court. She taught the king a new form of loyalty.
Ahab was not a private man making private mistakes. He was the king of Israel. When his worship bent, the nation bent with him. The midrash compresses that disaster into a single line: because of her, he was brought to become an idolater.
This is the frightening part. Jezebel does not need a long speech in this source. Her power is influence at the center. One person close enough to the throne can turn a king, and a turned king can drag a people toward ruin.
The prophets will spend the rest of Ahab's story fighting the fire that began in that room.