Photo-real fabrics are certainly one of the most difficult things to achieve in 3D, especially the large fold in the duvet towards the pillows (which looks deflated in this render). My advice is:
Provide your artist a high quality close up swatch of the fabric/type.
To match this swatch Poliigon have some great fabric materials/textures. https://www.poliigon.com/textures/fabric
From my perspective I would say the wrinkles/folds need softening by about 50% in the geometry.
Use a subtle displacement for the smaller wrinkles that appear throughout (between the larger folds).
Again that last 10% of quality adjustment is super hard so expect it to take time or additional budget since its top-tier kind of work.
