household hint (because you know I'm just a font of those): using 4 oversized rubber bands, one on each corner of the duvet and its cover, has revolutionized my sleeping life. it even stops the blanket on top that used to get thrown off during the night from winding up on the floor. Bed Bath & Below has some little holder clamp things for inside the corners, not sure of it would be an improvement; the elasticized corners are fairly inobtrusive already.
The solution to impostor syndrome is to accept that you are in fact a fraud and just get on with it.
