Typr is an open-source and customisable editor for React.js. It's built with Tiptap.dev, and readily integrates with your user system and CMS. As well as being a rich text editor, it handles content loading, creation, and auto-saving out of the box:
There's also user state management with customisable menus - play around with the demo site and you'll see!
This editor is currently live in use right here on Prototypr, a platform built with Strapi and Next.js, but it can be used with any Content Management System. Give it a star on GitHub if you find it useful!