Differential Equations is often called Difficult Equations for a reason.
You may have some more success in other areas of advanced math, particularly abstract algebra, graph theory, and related fields. You'll find more connections between that and what we do as developers than between programming and differential equations. And not just in the sorts of problems we solve (routing, etc.), but also in mapping between the structure of programs/architectures and concepts in algebra and graph theory.
Well, they are indeed difficult if you want to develop a new method of solving an equation or if you have discovered a new type of equation (which does not happen a lot these days). Otherwise, solving a differential equation seems to be not much more than simply a matter of recognizing a pattern and choosing the corresponding method.
Fair. I have no anticipation of being at the cutting edge in math either. One thing that I have found, though, is that as I've explored (particularly in programming and CS) more areas, that reviewing the math I had trouble with in college it all seemed "easy", or at least easier. An advantage of age/experience is the ability to draw from our numerous experiences and produce better (for us, personally) analogies with the material.
Another crucial thing for me (post-college) is the absence of grading or immediate external or internal pressure. If I have trouble with a math or CS concept, I just set it down. It has no impact on remaining employed or future job prospects (well, mostly, some geometry and trig refreshers were good when doing some geographic stuffs; learning some languages were critical to a job, but that's not theory). Additionally, I removed the pressure from myself. If I don't get something, I don't (as I did in college, which led to other problems) see it as a personal defect or deficiency. It's just a fact, I simply don't understand it. I re-read the same material over and over across a several year period (Knuth's Concrete Mathematics) before certain sections of it became accessible to me. I desired to understand it, so I returned to it. But despite the desire, I didn't feel any external or internal pressure to understand it at that precise moment. When understanding came, it was a good feeling. But when it didn't, it was just a thing.
Same here. I really wish I could go back to school and relearn some stuff I ignored back then. Back then I had to learn a lot of stuff just because but now I understand how they can be useful.
same with history. In school it was boring but now I listen to historical audiobooks all the time and love it.
You may have some more success in other areas of advanced math, particularly abstract algebra, graph theory, and related fields. You'll find more connections between that and what we do as developers than between programming and differential equations. And not just in the sorts of problems we solve (routing, etc.), but also in mapping between the structure of programs/architectures and concepts in algebra and graph theory.