But opportunities always exist. If you are not ready, when the opportunity comes, you can't catch it.
First of all, you should constantly improve your professional level, do what you love and do what you can. This is professional ethics and the law of the workplace. If you can't do it well, others will think that you can't even do your present job well, let alone promote you.
Charge more, don't be satisfied with existing knowledge. Since you want to be a math teacher, you should learn more about this and continue to cultivate deeply.
Finally, we should be volunteers. Timing is very important. We should be patient, wait for a suitable and sure opportunity and make a bold attack.