Blue Prism is a good tool to start learning RPA with, but as Andrzej already pointed out: it's not free. Not even a little bit!
UIPath, however, is free! (for small enterprises). The coding is in VB, which is .NET's predecessor. UIPath is also growing and used (currently) mostly in Eastern Europe (as far as I know).
In my opinion though: you're a developer. Whatever RPA tool you'll pick up is going to be child's play as there's very little coding involved among the more popular RPA tools.