Question

I’m familiar with solutions that will automatically wrap to 80 characters, etc. But fill-paragraph lets me wrap things to 80 characters (or whatever) when I want to, which is convenient.

Answer 1

I’m not familiar with emacs or its fill-paragraph, but it sounds like you’re looking for gq. It takes a movement, so either highlight what you want to wrap or use a movement command. E.g. gggqG will wrap the entire buffer.