I've been looking for something like this but I have a question for you before I think of purchasing. Aren't Datacenter proxies much worse for getting banned and such?
From experience I'd always assume that C++ would be faster simply because of how much you can optimize its methods for making calls but its the same for C# I think that both C# and C++ would always be like 10x - 40x faster than python if not more.
Python is a powerful language for a lot of reasons but its not as powerful as C++ and its also not build with speed in mind.