The biggest lesson I learned working at Dropbox was how toxic python is. If you have an unmanageable python code base, and hire Guido himself to help you fix it, he'll dig you into an even deeper hole and then quit. Which honestly was an extension of my experience at Google. When I left Google for Dropbox, python at Google was also in crisis. These two companies cemented my "python: not even once" stance.
I would say that in general dynamic type languages are problematic in a large codebase without strict safeguards (Any everywhere, untested paths, lack of test coverage, large methods with different return scopes, etc.).
I've worked a long time in C++ land in large codebases and the issues there are different, but to undig a project from the spaguetti land is like pulling teeth.
