Go and study applied mathematics. There may be few courses in analysis, and real analytical functional analysis. Those pure mathematics are extremely difficult, and it is more convenient to transfer from computer to finance after studying applied mathematics. Probability theory should be more practical as you learn it. Probability theory is very helpful for postgraduate entrance examination, and it is much better than looking for a job now. See if you want to do the analysis and research of number theory.

Only education and foundation? Then you must choose basic education. I think the road is a little narrow, and if I become a teacher in the future, basic mathematics may not have no advantages. I think basic mathematics has a good foundation and a good development prospect.