I agree with RedRyder. I have Garnet Hill flannel sheet sets for winter and they are my favorite sheets. I have a blanket from there too. All wash well.

When I saw OP's photo, I thought of green bedding to kind of color wash the room in greens (on my laptop the carpet, chair and accent wall are variations on olive toned greens). Looks like a calming space!

I’d actually consider a duvet insert with interchangeable covers rather than committing to one quilt color. A quality down duvet gives you a great quality foundation, and then you can change the cover seasonally or whenever you want a different look. Cream or taupe could be beautiful here, but you could easily switch to sage, denim blue, or something warmer later without replacing the duvet itself. I run a bedding store called Luxury Sleep Shop, and that flexibility is something people really appreciate. It lets you change the personality of the bedroom without having to buy a completely new piece of bedding every time you get tired of the color.

I always prime the wall behind the sample or post on white background - current wall color really impacts samples in my experience

I do my own large samples on large poster boards with 2 coats of the color I want from a sample can . Testing on an already painted wall is never the best . The tiny little samples are useless other thna getting ideas for what might work. Make sure that sample can is also the same sheen you will use. The bonus with the poster boards you can move them all over in differnent lighting and times of day.