In most places, that shouldn't be a huge problem. You have at least gotten some generalized mathematical insights. Specific insight within a narrow subfield requires more work, but that is necessary in any doctoral program.

The only real difficulty is getting accepted to a program, and that, might require finding a supervisor who is willing to take you on. But you don't learn that until you try it. Note that requirements differ widely around the world, both for application and for earning the degree. You need to learn those requirements and make a good application.

Note that competition for many programs is very high.

To see specific requirements typical of various countries see: How does the admissions process work for Ph.D. programs in Country X?

In most places, that shouldn't be a huge problem. You have at least gotten some generalized mathematical insights. Specific insight within a narrow subfield requires more work, but that is necessary in any doctoral program.

The only real difficulty is getting accepted to a program, and that, might require finding a supervisor who is willing to take you on. But you don't learn that until you try it. Note that requirements differ widely around the world, both for application and for earning the degree. You need to learn those requirements and make a good application.

Note that competition for many programs is very high. And, you don't enter a doctoral program to prove that you don't need it. You are expected to learn what is necessary.

To see specific requirements typical of various countries see: How does the admissions process work for Ph.D. programs in Country X?