I have similar thoughts. Wanting to write something, but unsure of what nugget of an idea to run with next, looking for interesting open stories to contribute to just for fun, an/or writing shorter stories (2-5 chapters and done). That or tackling a bigger idea I've been working on, but am afraid I'd have to abandon it due to the time investment.
I think if you "abandoned" an open concept story idea, leaving it open for others to contribute to, I don't think it would be too big of a sin to readers. Obviously any new authors might not have your voice or same concept of the story, but it could live on without you.
Example: Story -- "You're a poor, sex-crazed college student who finds a magic hoodie that lets you control the minds of everyone on campus." There's no real plot or story there, though you could explore one plotline or scenes and then "abandon" the story for others to explore and expand.
A more linear story with a more concrete or single plot might upset some readers if they don't get that story completed... or have to wait for someone else to adopt your abandoned story. Even then... (see above about voice, story, and concept).
In terms of short stories (2-3 chapters), I do see those pop-up from time to time. They don't seem to get too much traction (Likes, Faves, Views, etc.), but if you don't care about that stuff it's worth a shot. You could also do something similar to your '
Ryan's prompts and scraps' story and make a hub "story" for your shorts. Tagging could be a mess if you explore different categories and kinks, but you could maybe list those in a top or bottom "A/N". I've thought of doing the same with random ideas I have that aren't worth a whole big CHYOA story on their own.
Example: [main "story" title] 'Random Yarns from the Warden' and your short stories as the "chapters" on the main page.
