Suggestion: Loans and scholarships for STEM manors only.
Majors
I think that is too narrowly focused; there are other career paths that are good, and there are too many idiots who try STEM and drop out who should not have been given loans. To solve both problems, just having all federal loans reviewed by actuaries who honestly assess loan risk based on all available information like for any other loan-- the student, their family, the desired major / school and likelihood of future earnings. If a student has performed poorly, has poor credit history, and is going into a major that is not likely to produce a sustainable wage, then they can only borrow up to $x.
Alternate suggestion: make student loans dischargable in bankruptcy again, and make the college co-sign the loan. If their graduates don’t get jobs, the college gets to eat the cost of educating them.
Suddenly, colleges will have an incentive to NOT give loans to students who are unqualified, and to eliminate majors which do not result in employment.