Which should be prioritized in learning: Tawhid (monotheism), or Iman (faith) and beliefs, or the Qur'an first, and what comes after learning most matters of Tawhid?

The way of the Salaf was to learn faith before the Qur’an. They would not move past verses until they understood the faith and action contained within them. One should begin by learning faith. If this is difficult, let the Muslim memorize what they can and strive to act upon it. The imams began teaching children to memorize the Qur’an to accustom them to it, and this is what the followers of Imam Ahmad continued. So, if a Muslim learns the issues of Tawhid, let them follow the first method as much as possible; otherwise, let them aim for correctness and come close.