This tool allows the document to be created using CKEditor 5.0 and then uses http://annotatorjs.org/ to annotate it. The teacher can annotate and grade the paper and the student can see and update annotations. The teacher can lock the submission. All in all pretty cool. Here is a cool video:
https://www.youtube.com/watch?v=n2qz6XpxZ1Q
If you want to play with the tool go here:
https://www.tsugicloud.org/tsugi/store/test/ckpaper
You can use it as one instructor and three students.
You can use this in your LMS via TsugiCloud with a free key or if you are super cool and already have a campus Tsugi it is now available in the Manage Installed Modules admin section.