Take the example around me as an example. Most of my classmates take Chinese, English and politics. I have learned a lot by taking these three exams, but there are fewer people taking science exams (of course, I don't rule out the limitations I see as a liberal arts student).
Subjects with relatively saturated number of applicants:
History. You need to be particularly interested in history, do well in the history test, know more about history, and you can choose to apply for it if you can teach your classmates. There are many applicants.
Politics. His answer is more framed. In high school, comprehensive politics is just a template for answers. It needs opinions and explanations, so it is relatively easy to pass and there are more applicants.
English It is a subject that most girls will choose to take, because girls will have better English scores, stronger language skills and more applicants.
China people. If you need to write a composition and other things that are biased towards words, you will generally get a score if you answer it, which is easier to pass. But because there are many people in these three courses, he may not be so short of talents;
Subjects with more employment opportunities:
Mathmatics is more difficult to teach, because I was studying mathematics at that time, and he needed you to write a teaching and research plan or something. But it is better to teach in the future. Now math is a headache for many students, so a good math teacher is too important, but you must make sure that you really learn math well and are interested in this subject, otherwise you may be questioned by students in the future.
Geography. Unlike political history, which tends to be scientific, there are relatively few good geography teachers and fewer candidates.
Classification. I feel that it has always been a good job, because many units need engineering majors for recruitment. Many schools are short of teachers in these subjects. In my opinion, more difficult subjects may be better and more popular. Look at the websites of those schools that recruit teachers. In fact, there are more teachers in science and mathematics, while teachers in arts and sciences are relatively saturated with teachers in English and Chinese.