Coding in VBA kills more brain cells than alcohol! I am not a big fan of VBA, but to each his/her own.
You can still use them to build programs to backtest strategies as long as you find the software companies that provide you the compiler. OP is just looking for some scripting languages to build some scripts for backtesting? Both languages are quite powerful I find even though they were a bit platform-specific. C# is actually a very dynamic language.
EasyLanguage is tied to the platform so isn't really an option if you want to use other brokers or data of your choice.
Amibroker + AFL is fast and capable of complex system implementation. It can be controlled via OLE using JScript, and VB. It also has a "plug-in" for Python. It takes time to learn AFL but experience programmers should be OK.
Which would I learn (assuming I didn't already know it)? Python How and where? Videos, books, websites, and just doing it.
Most likely, I will go with Python. Leaving apart the technicalities, it is a very simple and useful language. One thing that I really appreciated about scripting languages is that they require less of coding as compared to other novel programming languages. Python also has its influence in the development of data science.