The best alternatives to OmniaWrite are Ulysses, Haven, and Inkvite. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of OmniaWrite?
AssemblyAI— Speech-to-Text API with superhuman accuracy
A pleasant, focused writing experience combined with effective document management, fast syncing and flexible export options make Ulysses the first choice for writers of all kinds
Taleforge is an app created to help authors practice their creative writing skill. It gives you a starting prompt and a word target, then goes on to pose additional challenges for you to incorporate in your story.
txtpad+ is a easy to use notepad that lets you open, create and edittxt files. 250 promo codes: https://www.promies.net/promotion/20626924-57fb-450b-84aa-408b586424cd/