Neovim can can certainly be an IDE, but its complexity comes from having a lot of features to rapidly edit text. d5d deletes 5 lines, vwwy selects two words and yanks them, gg returns to the beginning of the file, etc. It'll maybe do some code highlighting out of the box but its featureset is about never needing to touch a mouse or leave home row.

It's about like notepad++ on Windows in that it's very good for quick edits of a file or otherwise manipulating plaintext but it isn't good out of the box for actual writing meant to be read by other human beings.