At a certain point my pattern recognition skills reached their limit to where learning each new concept was still the same, but I had a lot more trouble organically seeing and identifying when a particular technique was useful for a particular type of problem. Which is something that happens to a lot of different people at different stages of their math education, just happens to different people at different points.

And maybe I could've stuck with it, or used it enough to where I eventually got it easily the way I had done with all math topics before that, but I ended up steering the rest of my engineering education into topics that weren't as heavy on that type of math. More programming and logic and microcontrollers, less electromagnetics and radio signals.

In my experience, it really wasn't an "advanced subject" for me. Sure, the majority of majors who are trying to become doctors, CS, or computer engineers only have to take up to calc 2 (and diff eq) for their bachelors, but I still wouldn't say MVC or diff eq is an advanced math subject. Real analysis or algebra -- where you have to take a math course on mathematical proofs before taking these classes -- is where I'll say math becomes more abstract on its applications and advanced.

Diff eq was not challenging at all, I spent probably 6 hours a week on average (which includes the 4 hours of lecture). Its as simple as solving a linear equations, with it being slightly more tedious. If you understand derivatives, integrals, and partial fraction decomp (for Laplace transforms) its a breeze of a class.

MVC on the other hand was slightly more challenging, but having finished calculus 2, that too was also very enjoyable.

Point is, MVC and diff eq aren't hard classes I wouldn't even call them advanced classes as that title goes to analysis.