Questions about house construction - Tips from experienced builders

Regarding your questions in #1:
9 sqm for the technical room is completely sufficient (6 sqm for technology plus 3 sqm storage for drinks and supplies), but then a storage room in the garage/carport should also be kept for the lawnmower and all that stuff. A storage room or utility room on the upper floor would be valuable for seasonal storage, washing, and cleaning supplies.
As a wardrobe, a small room or large built-in closet would be great. Under the stairs, a storage room can also be planned.

Really? But nothing fits there either... the kitchen is even more cramped, the wardrobe and the bathroom are just as unusable... the door in the bedroom is less than 60 cm from the wall, etc. etc.

Expandable because of the better stair location :)
For example like this, but also quite different options possible

Hello Yvonne, hello BeHaElj,

thank you for the feedback, I was somewhat surprised that the criticism of the floor plan turned out to be so "devastating." Until now, the floor plan seemed logical to us.
you are right, I will have to draw a site plan again, according to your suggestions, a complete restart/replanning seems unavoidable to me. I would like to involve an external planner, the problem is the costs - our budget is very limited.

Thanks also for the sketch, that is a good idea - until now we were also not entirely sure about the shape of the whole thing (square vs. rectangle). Should we really move away from seeing the south side as the main side and instead plan the west? What is the most sensible way to plan the rooms? Should the north not be completely neglected after all? In our case, the neighboring properties have their south side to the north.

Thanks again for the assessment, it’s good that there are such forums....

Regards, Charly

My sketch is a standard floor plan that you can get cheaply from many house companies. A west garden has enough sun. There will also be sun in the north, but the room lighting in the north will be somewhat lower. An office as well as a west living room will be able to live with that. Draw your plot with the neighboring buildings and see where you can imagine light in the room as well as peace or communication in the garden.