You don't need to pursue a second undergraduate degree if you just need to fulfill certain courses for graduate admissions.

Check out: https://ccaps.umn.edu/non-degreeguest-students

See if other schools of interest have similar programs if that one isn't a good fit.

See if you can take courses for credit/get research experience. Then apply for your desired graduate programs.

This is a good way to get letters of recommendations from professors too.