The best alternatives to Arc Studio are Scrivener, Typewriter, and editorr. If these 3 options don't work for you, we've listed a few more alternatives below.
Scrivener is the go-to app for writers. Used by bestselling novelists and new writers alike, no matter how you like to write or what you're writing, Scrivener unites everything you’ll need to create, research and arrange your manuscript in a single, powerful package.