WebDAV works well enough for remote file access, but it's too slow for me to foist on anyone else.
And I used Collabra to do some shared document editing, but it was a pain to set up (and still feels fragile). WebRTC has never worked, and anything on the #Nextcloud WebUI is awful.
But Nextcloud is the least awful thing I've found that does these things, so I'm sticking with it for now.