In some ways, the language you know best is the best language, but there are some caveats. Or, at least a language with the same underlying paradigm as the one(s) you know: procedural, OO, functional,...
If you are willing to learn a new language, it is more likely to be the available libraries that already exist and that are useful to your needs that is more important than the language itself.
I do most everything in Java and find the existing libraries very useful. In other OO languages, I've had to work hard to incorporate other libraries, not built for the language at hand, but available to import. IIRC, Python had that issue in the past, but suspect that problem is solved.
In general, investigate available libraries that are part of the language "package". Perhaps look at some existing projects and see if they seem reasonably similar to what you want to do.
I concur with Buffy that the language you know is largely the best language to work with, particularly because you're not working on particularly specialized problems. There is a mathematical bent to what you are doing, but that is well within the capabilities of essentially any language.
If you want something more mathematically oriented, you could try Python (it has very good libraries), R, MATLAB, or (if you want a wilder adventure) Mathematica or Scheme, but I don't expect you'll find a significant speed-up in your work flow.
Now, that said, I wrote that list of languages in the order I expect you'd find most-to-least familiar. So if you are just looking to expand your programming horizons, take my list in reverse and go one some crazy, mind-expanding adventures.