If you know the material well, it is best to take the credit and move on, since retaking a college course that you already did well in looks like grade-grubbing. Besides, why waste time and tuition learning what you already know instead of learning something new?
To check how well you know the material, you can try the old final exams from your college’s courses which you may skip. However, the next obvious math courses you would take as a CS major (discrete math and linear algebra) do not depend heavily on calculus and multivariable calculus anyway.
Regarding transferring, make that your goal only if you have no affordable options of schools with good CS offerings. And if you do need to transfer, note that HYPSM type schools admit very few transfers, so they are even more of a reach.