Your scene seems simple enough to have so much noise. How long have you been rendering? How many iterations?
Try removing the walls and ceilling. If the shadow effects that you want disappear, add the walls again, but try to add just the walls that do the shadow effect. Closed places takes too much time to render due to lighting effects. So remove whatever you can, otherwise it'll take hours to render something decent.
A good call is to render a x2 resolution (Ex: 1080x2 = 2160) and use post denoise filter in the end of the render (Ex: Max iterations = 300 and Filtering iteration at 290). Depends on the scene but, about 300 iterations is ok. Then go to photoshop and reduce the resolution by /2(Go back to 1080p).
For your scene i would render only the models on the bed and add the background after using photoshop. It's faster and the result is good.
