In the case of financial crisis, should I resign?

No, this is a good opportunity to exercise you. Many people left, many people will come back after the crisis, but you persisted. Of course, you have done a lot during this period, but you have also learned a lot. Even if you later find that this company has no future and you want to quit, go ahead. You have experience and can do anything. Really not good. You know when to do it yourself.