That is incorrect. Both are pretty barebones from the start and have a big pool of extensions to get the functionality that you need. It might be more involved on the vim/nvim side, but that is more of an accessibility VS personalization thing.
There are even sort of distributions for nvim that bring you all the common functionalities already configured.
When choosing a bug, if you start with one that is possible to reproduce, it might help following the instructions to reproduce it while debugging the app and observe what happens. This can be a way to start understanding how it all runs. Bugs without context or hard to reproduce are usually more complicated and you might need a better knowledge of the code to have an idea of where to look.