I would personally stick with C++
It will have higher pay going forward, as its a "aging" language
As for what to do, I would make an application
This could be a game (UE 4 has great C++ support) or anything really
I would check out this guy on youtube for some better advice
https://www.youtube.com/channel/UCZ9qFEC82qM6Pk-54Q4TVWA