Look, this is such a specific niche that you really have to know where to dig. Most big platforms heavily filter or ban this content outright, so dedicated forums and smaller, older websites are usually the only reliable spots.
I've had decent luck with sections of 'Lush Stories' that haven't been purged yet, but you have to use very careful tags—think 'age play' or 'ABDL' paired with 'strict' or 'regression'. The quality is a total mixed bag, though. A lot reads like hastily written fantasy without much emotional grounding.
What I search for, personally, are stories where the power exchange feels psychological and earned, not just a quick setup for the kink. There's one author on a forum called 'The Overflowing Crib' who writes these slow-burn narratives about domestic tension and reluctant caregiving that are weirdly poignant. You won't find that depth on any mainstream site.
It's a hunt, honestly. Bookmarking authors you like is more productive than searching by trope alone.