Has the verse of the Hijab in Surat An-Nur been abrogated by the verses of Surat Al-Ahzab, and is the Niqab recommended to the degree of being obligatory?

None of the scholars have said that the verse in Surat Al-Ahzab abrogates the verse in Surat An-Nur, and there is no contradiction between them. The verse in Surat An-Nur: "And not display their adornment except what appears thereof" (An-Nur:31), was interpreted by Ibn Mas'ud as referring to clothes, or what appears unintentionally. The verse in Surat Al-Ahzab came: "O Prophet, tell your wives and your daughters and the women of the believers to bring down over themselves [part] of their outer garments. That is more suitable that they will be known and not be abused" (Al-Ahzab:59), to emphasize the concealment of a woman's entire body from non-mahram (definition) men.