Self-study is certainly successful, depending on the purpose of your study. If you are a non-major or don't use much (you say there is no mathematics in undergraduate course), then learn the spirit and method of mathematics, and knowledge is secondary. In this way, don't generalize from the beginning, otherwise you will lose your way and have no strong driving force. Choose a few interesting topics, such as series, feel the understanding of infinity, such as geometric axiomatization, and feel one of the basic methods of mathematics in the traditional sense. With this interest, let's talk about systematic learning. You can choose advanced learning materials and stipulate how much to read every day. The test standard is to do questions. After reading this textbook, you can read another similar textbook and compare yourself, and you will "begin to understand" unconsciously. Three hours a day is enough for you to master the basic concepts and methods of advanced mathematics (for non-professional use) after one year.

It should be noted that it is difficult to self-control and maintain enthusiasm for a long time in self-study mathematics. The teacher said that many things we learn are forced, and learning always changes, which is very painful and boring, which is not in line with human nature. Hehe, I suggest you start with your interests, from simple to complex, and don't be greedy. The key is to start when you do it and come out when you do it. Calm down and spend more time on 2-3 topics.

As for the training courses, in view of the general shortage of university education, university teachers generally go out to do projects or topics, and do not do too much basic teaching. You can just find a school that offers large classes-advanced mathematics belongs to public mathematics, and many students learn to offer large classes.

When is it not?

Why don't you give me two points first, then you open a question and wait for a better answer? Hmm. How interesting