What is the authenticity of the statement that visiting Kairouan seven times is equivalent to performing Hajj, and are there prophetic hadiths that confirm the religious importance of Kairouan?

Visiting Kairouan with the intention of drawing closer to Allah is a lie, a fabrication, and an innovation (bid'ah), because it was built after the death of the Messenger of Allah, peace and blessings be upon him, and the cessation of revelation.