I think the author is writing JavaScript which certainly helps. Some languages just have terrible support in Vim. C# was okay-ish, Java was annoying, Kotlin is almost non-existent. As soon as you either want tests or debuggers more integrated into your editor, it gets difficult even if the language is not very IDE driven.

But I used neovim for a year at work. I write Python. I can totally see how you can live in neovim for languages like this. But I missed a proper test explorer and debugger though.

I don't think I'd go back to VSCode though. Either JetBrains or neovim. VSCode is in that awful middle ground spot where it's great if you are tying together tools and extensions anyway but if your whole suite of tools is supported in JetBrains products, I'd rather use those. Or use the tools on the command line and stick to neovim.