There are a few ways to get linting of prose (grammar and style, not just spellcheck) in Emacs. Unfortunately, there is no good language server implementation for the popular open-source command line tools. The best option right now is probably
vale gives better suggestions.
|Library||Language server?||Emacs package||Notes|
|Vale||No||flycheck-vale||Seems like a good alternative for Grammarly-like linting, emacs package is out-of-date|
|LanguageTool||Maybe later||flycheck-languagetool flymake-languagetool emacs-langtool||Requires java, poor performance when using cli|