I know of a short story on becoming a mouse, but that one’s focus is something euthanasia adjacent.

thank you for your service

Short stories and flash fiction avoid this problem by having genre conventions that allow for focusing only on a specific scene. Ploughshares in its recent Winter edition has a fiction piece that’s three paragraphs long, which I thought was an appropriate length for the content.

I think it’s somewhat common for writers to start with writing shorter pieces. GRRM comes to mind.