One of the best classes that I had was very hard in homeworks but was easy on the grading. It was literature and art class taught by a lawyer. I felt that I grew up a bit after that class. The class was also rated high by students
Undergrad feedback I wouldn’t trust at all regardless of major, Masters is major-dependent (ce, cs are particularly screwed) and phd candidates are probably fine. Simply by looking at the why the general population is even in the major (eg ask an undergrad and the reason is probably not actual interest in the subject: parents, jobs, money, dropout-major, couldn’t decide, best grades in hs, etc). Their feedback will naturally reflect the misaligned incentives
If your interest in feedback is to make sure the teachers are actually good at teaching, anyways.