Don’t think it’s so unrealistic to make a sterile green environment with fake plants. Fairly certain it doesn’t matter too much.

You're not wrong. ICU delirium is a serious problem.

https://www.statnews.com/2016/10/14/icu-delirium-hospitals/

But it's tough to make improvements. Regular hospital design is (roughly) optimized for staff productivity. They need to be able to treat and monitor many patients simultaneously which requires clear sight lines, good lighting, and a high level of automation. A more humane hospital design would also require more staff at a time when we already have a severe shortage. Where would the funding come from?

Hospitals are not "peaceful relaxing environments". They are large scale industrial operations designed to process as many people as possible. There simply aren't enough resources to afford every single person a "relaxing environment". You do the best you can for as many as you can. All this "relaxation" stuff will quickly be converted into spare capacity the second large numbers of severely wounded people start showing up at the emergency room.

If you're a multibillionaire then obviously you can just hire and equip your own private medical team that will focus 100% of their attention and care exclusively on you and your needs. The vast majority of the humans will never have that luxury. Normal people enter the system and are processed like everyone else.

I suspect the patients would fare better if active noise cancelling headphones were issued to every patient.

I've yet to see a study that shows noise cancelling headphones reduce patient mortality in any way whatsoever. Until there is such a study, money is better spent on things that are actually known to reduce mortality. Such as drugs.

I honestly believe that a pair or noise cancelling headphones and an eye mask would have statistically noticable effects on outcomes. The bright, noisy environment of a hospital makes good, natural sleep basically impossible and that is brutal on even healthy people.

My ward even managed to have the (networked digitally controlled, and do presumably very expensive) lighting set up so the night lighting was inside the curtains and shining directly into the bed spaces, and the main ward lights would come up if you touched the wrong thing (even the nurses weren't quite sure exactly what the proximal causes of lighting changes was). With the pumps alarming the whole time (about once per night, per patient, up to 20 minutes until resolution each time) plus all the other regular medical checks preventing any extended quiet time, it was absolutely exhausting at a very deep level.