> I recommend checking out the chebfun family of packages.

There's also an introductory textbook about ODEs ("Exploring ODEs") that uses chebfun [2] throughout.

As well as the original MATLAB implementation, there are now implementations in Julia, Python, and some other languages [3].

[1]: https://people.maths.ox.ac.uk/trefethen/ExplODE/

[2]: https://www.chebfun.org/

[3]: https://www.chebfun.org/about/projects.html