Is there any evidence from the Sunnah that reciting Surat Al-Muzzammil causes wealth?

What you have read about the فضائل (virtues) of Surat Al-Muzzammil is incorrect; it is a fabricated (Mawdu') hadith. Ibn Al-Jawzi mentioned it in "Al-Mawdu'at" and Al-Shawkani in "Al-Fawa'id Al-Majmu'ah," and the Huffaz (hadith memorizers) unanimously agreed that it is false. Many hadiths were fabricated concerning the virtues of the Quranic surahs with the aim of encouraging people to read the Quran, but this constitutes lying about the Prophet, peace and blessings be upon him, and its perpetrator falls under the warning of his saying: "Whoever intentionally lies about me, let him take his seat in Hellfire." The fabricators of these hadiths admitted that they forged them to turn people's hearts towards the Quran. As for Surat Al-Mulk, it has established virtues.