I would generally set up a face in front of the knob and apply the texture to that face. Then I would set the texture to be projected, sample it, and apply it to the front of the knob. I’d unsoften the edges around the largest diameter of the knob so I could paint the front dome separate from the neck. Typically a knob like that would be turned such that the dome would be mostly end grain so I’d use one of my cherry end grain textures.
Making the mattress was an unexpected learning experience. Just creating a profile of the edge and using follow me produced different results from what I was looking for and a nasty little hole:
That first segment from straight to curving ends up not making a wedge segment. I went about it in another way, and got what I intended, but the process took more thought.
As for the mattress corners, the trick is to set up the profile outside the path.
Pillows: there are various tools for that. You could use Vertex Tool for that. For the sheets and duvet, Clothworks would be a good option. I was taught to make a bed so you could bounce a quarter off it so that bed from the Warehouse bothers me a bit.
I’ve always found that less than obvious at least, if not counter intuitive, but it does seem to be a good practice.
In your example, the radius of the outer corners is greater than the depth of the profile so the resulting big, flat faces are also rounded rectangles. That’s not bad, in fact it all works more easily as a result than ending up with rectangles.