ᐅ Need for optimization? Single-family home with 1,400 sq ft plus basement

Hello,
we will sign our construction contract next week and would like to ask for your opinion regarding the current planning. The detailed design is still pending.

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Development Plan / Restrictions

Plot size 583 m²
Slope no
Site coverage ratio (building coverage ratio)
Floor area ratio
Building envelope, building line and boundary Max. gross floor area 130 m², access from south
Edge development
Number of parking spaces 2 independent spaces
Number of storeys Ground + 1 upper floor
Roof type Gable roof, pitch 33-45°, knee wall height unrestricted
Architectural style not specified
Orientation ridge runs from east to west
Maximum heights / limits Max. ridge height 9.00 m (29.5 ft)
Other requirements

Client Requirements
Architectural style, roof type, building type Knee wall 1.00 m (current plan based on 0.75 m, but will be revised)
Basement, storeys Basement + 1.5 storeys
Number of occupants, age Both early/mid-30s, planning for 1-2 children; 1 child, daughter 14 years old (stays every other weekend)
Space requirement on ground and upper floors 130 m² (1400 sq ft approx.)
Office: Family use or home office? Home office should be possible
Overnight guests per year Every other weekend (husband’s daughter)
Open or closed layout
Conservative or modern style Modern
Open kitchen, kitchen island Open kitchen with island
Number of dining seats 6
Fireplace Yes
Music / stereo wall Yes
Balcony, roof terrace No
Garage, carport Double carport
Utility garden, greenhouse No
Additional wishes / special features / daily routine, reasons for choices:
Large hobby room, potentially usable later as guest/children’s room, therefore also equipped with panel heating and light well;
no roof windows desired; there will be a glass sliding door between the hallway and living room (not yet planned);

House Design
Who created the planning:
- Planner from a construction company yes
- Architect
- Do-it-yourself
What do you particularly like? Why? Entrance area with guest bathroom; window planning on ground floor
What do you not like? Why? Stairs and bathroom on upper floor (not yet fully designed)
Price estimate according to architect/planner: 310,000
Personal budget limit for house including fittings: 360,000 including ancillary building costs (including landscaping)
Preferred heating technology: air source heat pump

If you have to give up something, which details / extensions:
- Can do without:
- Cannot do without:

Why is the design as it is now? For example:
It was difficult to design the ground floor because the entrance should not be on the south side, so there are not many options for the ground floor layout;

What is the most important/fundamental question about the floor plan summarized in 130 characters?
Can the living area still be optimized (is the living and dining area large enough)? Ideas for the upper floor bathroom design?