Is it true that whoever prays four rak'ahs before Dhuhr and four after it, Allah will free him from Hellfire, and when is the Sunnah prayer of Dhuhr performed?

It is recommended to pray four rak'ahs before the Dhuhr prayer and four after it, based on what was narrated from Umm Habiba, may Allah be pleased with her, that the Prophet, peace and blessings be upon him, said: "Whoever prays four rak'ahs before Dhuhr and four after it, the Fire will not touch him." These rak'ahs constitute the regular Sunnah, and the confirmed Sunnah consists of four rak'ahs before Dhuhr and two after it. The time for the pre-Dhuhr Sunnah is between the Dhuhr adhan and the obligatory prayer, and for the post-Dhuhr Sunnah, it is from finishing the Dhuhr prayer until the Asr adhan.