2D would really not be bad
The bow has something. I almost find it a shame that it is fragmented and divided into several rooms.
The draft seems too complicated to me. Every saved centimeter in the south garden is bought by an impossible volume along the northern building boundary.
The staircase might not run well like this.
If you want to enforce the quarter circle architecturally: then build it completely round as a multifunctional room on the ground floor and place an open spiral staircase concentrically in the imagined center.
Or: alternatively save a lot of money and realize a rectangular volume 11x10m (or wherever the max limits are). I would probably do that.
Take a look at the series "Grand Designs," there are plenty of interesting projects in tight spaces. Of course, building is different in GB – however, the ingenuity is impressive, as is the attitude of the builders towards compromises. One consciously accepts a disadvantage in order to gain an advantage. Often, attempts to think of everything and make everything perfect become either very boring and soulless (or very expensive).
The "cubature" can become a true beauty with an asymmetrically curved wall on one side. Everyone says that it’s impossible to paint a nose on a leg. With Picasso, that is "Cubism." I like the courage to curve – start getting used to custom furniture.
You have to try out the staircase somehow, I agree. The shape can also become brilliant.
How much time do you have? The plot, an open mind, and clear communication skills of the builders can be a great basis for an architect’s master thesis. That takes some time and surely a lot of fun.
The draft reminds me of a defiant attitude of the community regarding the mentioned "lack of cooperation." You don't mention something like that without reason
Is there a floor plan? I mean: 2D from above. very classic. I would really like to see that. I get a bit of eye strain from other 3D games. I definitely find such drafts interesting and shouldn't dismiss them right away.