Bedroom idea - bed / wardrobe arrangement

You don't build a house for 300 grand or so and then can't even place a minimal double bed with a width of 180! And that also applies to your kitchen, Yosan. And justifying it by saying that there is currently an even bigger disaster is not worth discussing.

It's not too difficult to fix the issue here either. I would simply go to your architect or draftsman with the problem and ask what he can do or how he envisioned it.
And it would be time to also draw in the rest of the desired furniture throughout the whole house to prevent disappointments.

The distance from the stairs to the wall at the top of the plan is 1.30m

One would need pretty much all the measurements for a correction. First, the stair measurements (length, width, rise, tread depth), then below the measurements of the rooms (WC, utility room, closet niche), hallway width, etc.

I only said that I see it as less problematic because I found that the width doesn't bother me in reality, even though I previously thought it would bother me. It's certainly different for everyone what they find comfortable/uncomfortable in this case... partly because of things like shoulder width, etc.