It seems to me that I'll need to install webpack as a dev dependency just to use plugins. Am I correct? If that is the case, CRA throws a long error:

It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "webpack": "4.41.2"

Don't try to install it manually: your package manager does it automatically.
However, a different version of webpack was detected higher up in the tree

@kumarharsh have you been able to figure out how to add the webpack plugin. no matter what I do it does not append anything into ENV for me and it can't set any global variables.

Sorry, I don't remember much (moved on from the project). I did manage to figure it out, but don't remember the specifics at all :)