More apps I do not need! I use Drafts on iOS for all text based work, I have used Ulysses because I could, did I need it no, but then need is an often overused word.
Now on MacOS I write in markdown in VSCode and its not always for code based articles either. These are saved/organised in a git repo which VSCode has very good built in management tools.
I have recently been reviewing all my app needs, gone are Evernote, DevonThink, KeepIt, Agenda App, etc etc.
PDF Files and client notes are now saved directly on iCloud Drive in my custom filing system. Files are either PDF’s or Markdown/Text this saves me all the worries of app switching and jumping on the shiny new product bandwagon. One app for text/coding on iOS (VSCode) one app for text on iOS (Drafts app, then usually exported to filing system) One folder per client or subject in iCloud with sub folders as needed.
All files follow the same naming convention for example Date-fileName.ext. Dates are in ISO format <2018-10-21> making searches and organisation easy. Shortcuts on iOS automates much of this as does Hazel on the Mac
Simple, and somewhat future proof.