Floor plan of a detached single-family house, with basement, 2 full floors

Hello everyone, we are currently planning a detached single-family house on a plot that is already in our possession. We have an architect on board, but we are also intensively involved in the planning ourselves. We are now close to finalizing the plans and giving the architect our go-ahead to prepare the building application. We would like to take this "for now last" opportunity to have our floor plans questioned by other people and to obtain other opinions to make sure that there is no major flaw in the basic planning.

Bebauungsplan/Einschränkungen
There is no development plan, accordingly §34 applies.
Size of the plot: 455 m²
Slope: Sloping terrain running west-east, dropping 2 meters
Site coverage ratio: 0.4
Floor area ratio: 1.2
Building window, building line and boundary: -
Edge development: -
Number of parking spaces: 2
Number of storeys: 2
Roof shape: -
Design style: -
Orientation: -
Maximum heights/limits: -
Other specifications: -

Requirements of the clients
Style, roof shape, building type: Classic house with gable roof and large gable dormer.
Basement, storeys: Fully basement with two full floors and the possibility to use the attic later as an office.
Number of persons, age: 2 persons, approx. 30 years old. Children planned.
Space requirements on ground floor, upper floor: approx. 80 m² per floor.
Office: Two home office workspaces necessary as we both work from home about 90% of the time.
Guest sleepers per year: Only sporadically, so can be neglected.
Open or closed architecture: semi-open.
Conservative or modern construction style: conservative
Open kitchen, cooking island: Open kitchen without island
Number of dining seats: 8, but when we celebrate, ideally room for 16 guests.
Fireplace: Yes.
Music/stereo wall: Not necessary.
Balcony, roof terrace: Not necessary since we have the garden.
Garage, carport: Garage with passage to the house.
Utility garden, greenhouse: No.
Other wishes/special features/daily routine, also reasons why this or that should or should not be:
It is important to us that the two offices are designed as appealing rooms and not just as a means to an end, as we spend most of our time in these rooms. The garden is also very important to us. Since the plot is on a slope and the neighboring plots to the west are higher, we have decided to fill up the garden. We gladly accept the steps in front of the entrance for this. The house is positioned on the east side of the plot because a second house will be built on the southern neighboring plot and we agreed on this arrangement so that both gardens will receive plenty of sunlight.

House design
Who developed the plan: The plan was created by us in cooperation with an architect. Fortunately, I have a mechanical engineering CAD system available, so we created the attached plans in this system and also use it to test and realize our ideas. We give the exported drawings to our architect, who then creates the "real" architectural plans on their basis or adjusts his existing plans if he has no objections or counterproposals.
What do we particularly like? Why? We especially like the roof shape and the broken-up facade on the east side. We are also pleased with the spatial layout and orientation of the rooms.
What do we not like? Why? Currently, we are not satisfied with the arrangement of the windows, especially on the west and north sides. There is still work to be done here.
Price estimate according to the architect/planner: Not available yet.
Personal price limit for the house, including equipment: €650k - €700k.
Preferred heating technology: heat pump (air-air)

If you have to give up, which details/extensions
-can you do without: second bathroom on the upper floor (for now), fireplace, pantry, space for piano on the ground floor.
-can you not do without: two office rooms.

Why the design is as it is now
We dealt with the topic ourselves for a long time and created many own drafts before looking for an architect. After talking to several architects and discussing drafts, we decided on our current architect. Our requirements and wishes have been almost completely implemented in the planning. Ideas from both us and our architect have been incorporated into the plans.

Some windows and doors are not yet drawn in the plans because I have not yet created a 3D model for this. Please don't be surprised :-). Of course, during construction every wall opening will be fitted with a suitable window/door. In general, the plans do not claim to be architectural plans. Rather, they are intended to visualize our ideas and concepts.
Furthermore, the house entrance was only drawn as an example to see how many steps are needed in front of the house. Please disregard the depicted staircase.

Thank you very much for your constructive input!

I think it's great how you are approaching the planning! But the budget and house size do not match my current understanding of construction costs per sqm. On top of that, the expensive terrain modeling. You would rather have to calculate with 800,000. Unless you live deep in [Thüringen] or [Mecklenburg]. You come to over 300 sqm of gross living area.

Four bathrooms, three offices, huge corridor areas. If your budget is fixed, then you have to - in my estimation - cut 100 sqm.

I still see some optimization potential, but it is not worth discussing as long as the budget is insufficient anyway.

I just don't understand how anyone can be so intensely involved with the topic of houses and then plan with a budget of about 700,000 euros for around 400 sqm of built-up area?

I also fear the plan has to be thrown away because it is too expensive. Or the OP will still break the piggy bank and take the mice out from under the pillow. But maybe you can also plan a size smaller and work more with the slope.