Is it better for a woman to work as a teacher, or to study the rules of Tajweed, or to combine both, taking into account that her husband's financial situation is good?

The basic principle is that a woman's staying in her home is better for her and a benefit, and her going out to work affects her domestic duties. This is preferable, unless there is a need for women's work, regulated by Sharia (definition) guidelines, that Muslims require, such as medicine and teaching for women. As for her going out to seek sacred knowledge, it is a virtue, an act of obedience, and a means of drawing closer to Allah if she adheres to the Sharia guidelines.