Hello,

You can't pursue a UG degree again as you are an graduate now.  it is not possible to hold two UG degree. Every stream has a learning path and it is one way. you can't mix up domains. UG->PG-> PhD (in same domain)

you can do MSc in mathematics domain specialization. There will be  good job opportunities when you have PG degree. If you want to work in research field then you can do PhD after MSc.

You can also apply for government jobs like banking, IT operation, management, finance, accountancy after graduation.

Hope it helps!