Single-family house 1.5 stories approx. 150 sqm floor plan DIY design

Hello everyone,
we are planning to build on a plot next year and have been thinking about the floor plan / site planning and all possible aspects for several weeks now. We already have 2 offers based on the floor plan for the house, but we are still not sure whether we want to build with these companies or go to an architect. Unfortunately, there was no extensive feedback on the floor plan, only an offer.
Therefore, we want to present the project here and gather opinions on whether this do-it-yourself floor plan is feasible and also sensible.

Development plan/restrictions
Size of the plot: 1460m², 59m x 24.5m
Slope: no
Floor area ratio: 0.4
Plot ratio: 0.5
Building window, building line and boundary: approx. 17m from the street front.
Edge development: not desired
Number of parking spaces: 2 desired
Number of floors: max. 2 full floors, upper floor as attic
Roof shape: gable roof
Style: single-family house
Orientation: SWW-NOO
Maximum heights/limits:
Further requirements: Should orientate to the adjacent development. Rear area currently leased (garden use / chickens / shed).
Access to the rear area should remain possible.

Client requirements
Style, roof shape, building type: gable roof, normal single-family house, knee wall approx. 140cm
Basement, floors: 0, 1.5
Number of persons, age: 2 adults (31 years) 2 children (2 years, twins)
Space requirements ground floor, upper floor: approx. 150 m²
Office: family use or home office?: Office not necessary if there is space for a desk.
Overnight guests per year: very few, no guest room. Space for a fold-away bed in the living room
Open or closed architecture: partly partly
Conservative or modern construction: modern
Open kitchen, cooking island: kitchen and dining room together, number of seats: 6 permanent but with reserve for 8/10.
Fireplace: optional
Music/stereo wall: normal TV stand + stereo speakers
Balcony, roof terrace: no
Garage, carport: carport, tool shed (basement replacement)
Utility garden, greenhouse: lawn + some utility garden
Further wishes/special features/daily routine, also reasons why this or that should or should not be the case

House design
Who planned it: do-it-yourself
What do you especially like? Why?
Ground floor: kitchen with light from 3 sides.
Upper floor: large children’s rooms, space for desk
What do you not like? Why?
Relatively narrow bathroom / utility room
Relatively narrow passage behind the seats in the kitchen or is that okay?
Chimney position not optimal.

Price estimate according to architect/planner:
Personal price limit for the house, incl. equipment: 260,000 without furniture
Preferred heating technology: heat pump (air or geothermal)

If you have to do without, which details/extensions
-can you do without: chimney
-can you not do without:

Why has the design turned out as it is now? e.g.
We want to have 2 separate living areas, so no open kitchen-dining-living room. However, we also want a large table for up to 8 people.
Since we currently also have a large kitchen and are satisfied with it, this was carried over.
The children’s rooms should be appealingly large and get sunlight.
The roof should be extended at the house entrance area (as weather protection, not visible in the floor plan).
What is the most important/fundamental question about the floor plan summarized in 130 characters?
Is the staircase in this shape possible without causing disturbance? Are there bottlenecks or potential for optimization?

Thank you already for your opinions!

I don’t want to clutter your thread. I can definitely imagine living in this as a house, except that I couldn’t stand the stair entry in the entrance area. Street shoes go across there about 10 times a day and slippers about 30 times a day. Currently, we have the entrance to the rental apartment next to the bathroom door. We carry small stones and dirt through the apartment all day. The most noticeable are always small stones from children’s shoes that then get stuck under the door and scratch the floor. But that seems to be a matter of taste; many current floor plan variants have it like that. My question: the 25 cm parapet height at many floor-to-ceiling windows, is that supposed to invite sitting? We are also currently considering 2 floor-to-ceiling windows in the bedroom and children’s room, and have come across the possibility of sitting on the windowsill. But 25 cm is too low for that, right? EDIT: 260k probably won’t be affordable even without additional construction costs, I think, with a heat pump. And is the clinker supposed to be built in or is that just decoration? We had asked for fun as well and were quoted 30-50k for clinker for the house.

I think it's quite good. What I especially like is your modesty. That you don't want to squeeze another 10 rooms in somewhere.

What I don't find so successful: the kitchen-dining area is very narrow and tube-like. The living room, on the other hand, has plenty of space. Here I would shift things around a lot in favor of the dining area. You can hardly get out to the terrace either.

Upstairs I find a lot of space wasted and in the end not really coherent. Attached is an alternative for the upper floor (stairs no landing):

I have never understood the stairs at the entrance (for the reasons mentioned above), unless it is a real space-saving miracle or has to make do with 109 sqm. Basically, I find the almost 40 sqm hallway somewhat generously planned. I don’t like the eat-in kitchen at all. Too narrow, too long. There is no space for a cabinet next to the table. In addition, the kitchen becomes very dark. The light from the south and west windows would not reach the work surface. The terrace door is blocked by furniture. If only one chair is occupied, you have to squeeze through. In winter, the west windows are not very useful. Sure, there is brightness in the living room, but you don’t necessarily need daylight there. I don’t find the bathroom too narrow at all. Better that than an uncomfortable dance hall. The storage room, that is, the utility room of 9 sqm, is borderline too small for 4 people. From where is the tenant supposed to access his property?

Hello rericht: We only chose the BRH25 because the lady of the house likes to place flowerpots on the windowsills. Additionally, I think it simplifies the floor structure (straight finish). Regarding seating: 25cm is probably more of a children's bench, comfortable is something else.
Regarding clinker bricks: One offer mentions something about 16k for the clinker work. We are still undecided about this: nice, solid, and durable vs. additional costs and thicker wall construction.
Regarding the staircase: Your objection is justified and sounds plausible. At first glance, unfortunately, I couldn't find an alternative to the current staircase. It would have to be rotated or be in a U-shape. Maybe something will come to me.

Hello Katja: Thanks for the quick draft. The idea of the jump in the kitchen wall looks quite good. In the living room, we do indeed still have some space left. We'll give that a try.
Your upper floor design with the separate office doesn't quite correspond to our ideas. Whether I have an office or a larger hallway with a desk and 2 cabinets, the space is the same. I rather hope that the feeling of the room is a bit better when you come upstairs and don't just see doors.

I rather hope that the sense of space is a bit better when you come up and don’t just see doors.

You are looking at a workspace for 4 people - PC, printer, file folders, and paperwork. Lots of cables, etc. Keeping a desk and its surroundings tidy works for very few.

Where is the vacuum cleaner supposed to stand?