Community Tutorial: How to Add a CPP Plugin to an Only Blueprint Project

If you install a plugin from FAB, the plugin will become part of your local engine, and you’ll have access to all its functionality from any Only Blueprint project.

https://dev.epicgames.com/community/learning/tutorials/19ojR/fab-epic-for-indies-how-to-add-a-cpp-plugin-to-an-only-blueprint-project