It's happened to me twice where I accidentally tapped "mark all as read" on bigger stories and have been really frustrated trying to find my place and see which paths I haven't taken yet. So is there a way to "mark all as unread"? If there isn't, I think that'd be an easy QoL improvement to the site for the devs to work on (assuming there's interest)
As of now, there is no way for the user to do that. As far as I remember, there is a single database line to save that information. Removing that line might reset all chapters back to the status unread. You could ask Friedman to remove the story read information.
