We don't study calculus in Ukraine - or didn't when I lived there. What is known as calculus in America, is actually a small portion of what we called Higher Mathematics. When you approach all of it at once, there is no one fundamental theorem of anything - there is a bunch of theorems, all of them fundamental, half of them unproven. What is known as the Fundamental Theorem of Calculus here is a tiny portion of integral and differential studies you sail through on your way to building three-dimensional functions. I honestly don't know, which approach is better. I prefer the all-out comprehensive way myself - but that could be just because that's the way I am accustomed to learning.
I do data analytics for a living, among other things, so I am one of those people who actually does use math daily. However, I think that is not the main advantage of having studied math. My father says, "Mathematics is gymnastics for the brain." When you do physical exercise, it's good for you even if you are not training for the Olympics. When you do math, it's good for developing analytical abilities even if you do not plan to use it professionally. So, I believe studying math and its applications (like numerical analysis) ultimately made me better at all my various jobs. Even when I washed dishes at the cafeteria on campus. It's amazing how much less loathsome washing dishes is when you start doing Gaussian eliminations in your head.