SHort answer, to my knowledge, is “no, at this time”.
The closest I’ve seen, is one of the notes apps that works with markdown. It’s not really collaborative per se though, although you can share the files created with it, with other users and have them edit them as well (although presumably not at the same time).
A future release of Next Notes will give you exactly this opportunity.
Please feel free to contribute in order to make this feature available even faster or just watch out for release v2.0.0, which will contain this feature.
I use https://github.com/icewind1991/files_markdown
Works quite well for markdown files. But not sure what happens if multiple users work in parallel
So, Next Notes will allow collaborative editing of notes?
Well I think it depends on what’s your understanding of collaborative. Working on a document in parallel isn’t planned yet, but sharing it and editing by another user is.