What does “powerful enough” mean?
The Visual Studio IDE is quite small on system demands, so keeping it open or not shouldn’t matter much, compared to the needs of the Unreal Editor itself.
Anyway, Visual Studio comes with a tool called “MSBuild” that you can use to build any solution/project from the command line. Here are the README instructions for UE4:
Just point MSBuild at the UE4 project and tell it to build the Win64 / Development Editor target, and it will do it.
Here’s the full documentation:
https://docs.microsoft.com/en-us/vis…e?view=vs-2019