Split-level floor plan on a slope with 140 sqm

Good evening everyone.
It would be nice if you shared your well-founded opinions and experiences with me and reviewed the following floor plan.

Bebauungsplan/Einschränkungen
Size of the plot: 800sqm
Slope: yes
Site coverage ratio, floor area ratio, building window, building line and boundary: No development plan. Development according to §34
Edge development
Number of parking spaces: 2
Number of floors: SplitLevel, 3 levels
Roof shape: split shed roof

Anforderungen der Bauherren

Basement: No basement
Number of people, age: 3 persons, 47, 41, 17
Room requirement: approx. 130-140sqm
Office: No
Overnight guests per year: 5
Open or closed architecture: open
Conservative or modern construction: modern
Open kitchen: yes
Number of dining places: 4-6
Balcony, roof terrace: no
Garage, carport: double garage
Utility garden, greenhouse: no
Further wishes/special features/daily routine, preferably also reasons why this or that should or should not be:

Hausentwurf
Who designed the plan: Do-it-Yourself
What do you particularly like? Why? open design, south-facing slope orientation
What do you not like? Why? Entrance area maybe too dark. Floor plan level 2 with WC.
Price estimate according to architect/planner: -
Personal price limit for the house, including equipment: 350,000-400,000
Preferred heating technology: air-to-water heat pump, photovoltaic, controlled residential ventilation

Wenn Ihr verzichten müsst, on which details/extensions
- can you do without: double garage with integrated roof terrace (can also be carport, then without terrace), air-to-water heat pump (can also be gas)
- cannot do without: controlled residential ventilation

Why did the design turn out the way it is now?
The initial plans included as few stair steps as possible. But since the plot already exists and due to the slope, barrier-free living is hardly possible, we have now become enthusiastic about SplitLevel. With two half staircases, the climbing up and down is kept within limits, and with WCs on each level as well.
On level 0 (south-facing), the son can let off steam, and even when he has visitors, he should hardly disturb us.
Levels 1 and 2 are each equipped with bathroom/WC and are designed open in the kitchen/living room area. Hall/stairs are kept to about 20sqm to leave as much living space as possible.
Storage/utility/housekeeping room is planned at about 18sqm.

What is the most important/basic question about the floor plan summarized in 130 characters?
Does this floor plan work?
Does SplitLevel work on this slope?
Is the planned budget sufficient for the house?
Build rather with an architect, or can a general contractor also handle such a slope?
If you need further input...?

Thank you very much in advance.

Have you ever created a thread?

Budget including earthworks, outdoor area ancillary construction costs
Will not be enough on a slope

Architect and general contractor both work. I would avoid timber framing.

Wardrobe is missing
Child/guest room quite dark
Kitchen the long row is impractical
Bedroom door is a bit too close to the bed

It would bother me that the bathroom is not on the sleeping level

The idea with the SL is good, but we already had that in the conversation, didn’t we?

Have you ever created a thread?

The church parking lot property with the middle staircase to the basement

I don’t think the implementation is good since almost all the rooms are not well designed.
The ears at the front in the hallway are not comprehensible, they ruin the rooms and otherwise have no added value, unless you place the doors differently and use a niche for a wardrobe.
The bedroom is very narrow but long. The central meeting point/focal point is too hidden for me.

Have you ever created a thread?

At the beginning of this week, the thread was still at this status: - continuing it there would have had more continuity in my opinion - so why the restart now?

I find it terrible and out of the question. Please commission the architect.

I agree with kaho674 and would urgently recommend involving the appropriate experts.