I had to re-think "desks" after breaking my collarbone two months ago, and spent a lot of time in my make-shift couch lay-down desk. While I had full control over my lower arm and hand, moving my upper arm and shoulder was painful. The only position I could stay in for extended periods of time was laying down, and I needed to find a way to use both hands without shoulder pain.
On day 2, I discovered that I could spend hours lying flat on the couch with my legs propped up with cushions and a laptop on my 45deg legs. In that position, I could use the computer two handed for extended times as if I didn't have a broken collarbone.
Coming into the office to work (as COVID has been eradicated in my part of Australia) was harder since more than 20mins in an upright position (chair or standing) caused my shoulder to ache.
It took me a couple of weeks to work this out, but I ended up using a large upright shaped bean-bag as my office chair. I could mold the beanbag to give my arm support and sit the more reclined position that re-leaved aches. Having an Ikea standing desk helped, as I get into the bean bag and then lower the desk to match.
It's healed enough now to use regular chair and standing desk, but I learnt a lot about me and desk positions.
My main conclusion (after 15years of having a coding job) is that variation is key. There is no magic seating or standing position. Even if there was, it would be become uncomfortable eventually.
While probably the worst seating position for my back and posture, I have kept the beanbag chair at work, because using it occasionally feels good.
And, when at home I have continued to use the lying flat on the couch position, because again, it's different to how I usually use computers.
Which brings me to my main thought on this project (which I love the idea of): It's too permanent. I'm sure it'll feel amazing and comfy for a few days (or even weeks), but at some point for my body, it'd become just as annoying and uncomfortable as a regular desk.