Short answer: Yes for USNA. I don't know enough about ROTC to comment on that so the below is ONLY for USNA.
EVERYONE at USNA takes the core curriculum, regardless of major. There are (or were) some tweaks in that Groups 2 and 3 (math/science and humanities majors) take an "easier" version of certain math, science and engineering courses than Group 1 (engineering majors). Or conversely, Group 1 takes a harder track. To be clear, that doesn't mean the courses are "easy," merely that Groups 1 does sort of an AP version compared to everyone else.
And, folks may validate out of certain courses. But everyone must take or validate two years (not 3) of calc + another high level math course, a year of chem, a year (not two) of physics, a year of cyber, a semester of EE, a semester of systems engineering and probably some more STEM that I'm forgetting. Plus navigation courses for (I think) 3 semesters.
USNA has a STEM-oriented curriculum. You don't have to love STEM but you need to be able to be successful at it, even as a Group 3 major. The reason is that, especially in your first two years, STEM courses comprise the majority of your course load. That means they are weighted heavily in your overall grade. So, if you can't/don't do well, your grades will really suffer b/c you don't have enough humanities courses in the first two years to balance out poor STEM grades.
Also, if you don't have any interest in STEM, your first couple of years at USNA will be kind of miserable b/c, again, that's most of your course load. After that, if you're a Group 3 major, the majority of your courses will be in your major/other humanities courses, but you will still have STEM courses throughout your four years.
One other note: There's no such thing as "Marine Option" for USNA. Service assignment is made first class year; until then, there are no guarantees.