Neovim is quite a bit slower than cat and echo.. in my experience.

Interesting. That tells me there's something wrong with my neovim config. When I open a file for the first time, it takes some time before it shows the contents of the file. It's not even a big config, but maybe I'm using a plugin that slows things down or something.

Try using Neovim without loading a config, just like a fresh install, and see how it is.

Yeah, it's due to something in my config.