Renovation of existing ground floor apartment - additional office

Hello everyone,
I am allowed to take over my parents’ apartment and now wanted to start with the renovation. Unfortunately, I have the problem that the apartment has 1 room too few for my needs (in this case a small office).
Now I wanted to gather some ideas here whether it is possible to redesign / structurally change the below dining room/living room/kitchen so that a small office can still be created?
Costs are irrelevant at first, what is important is that there is a sensible possibility:

Anforderungen der Bauherren
Number of people, age: 2x late 30s, child planned
Office: Home office?
Open or closed architecture: rather open
Modern construction
Open kitchen, cooking island: Yes please, if possible
Number of dining seats: 4-6
Fireplace: Yes. But should please be in the living room. Currently in the dining room

Hausentwurf
Who designed the plan:
- Architect: from 1985, no data available anymore
What do you particularly like? Why? Large living room, rear area successful (bedroom, bathroom, KZ)
What don’t you like? Why? Huge dining room as a separated area, like a large hallway; one room too few available

Warum ist der Entwurf so geworden, wie er jetzt ist? For example
House built in 1985, parents decided so

Was ist die wichtigste/grundlegende Frage zum Grundriss in 130 Zeichen zusammengefasst?

How can I carve out another room as an office (approx. 10-12 sqm) from the existing floor plan?

How can I carve out another room as an office (approx. 10-12 sqm) from the existing floor plan?

Costs don’t matter for now, what’s important is that there is a sensible possibility:

Then redesign the entire floor plan with an architect and structural engineer according to your needs. Otherwise, you have a problem cutting off 10 sqm somewhere.
Wouldn’t a small desk in the hallway or bedroom suffice? I don’t know your needs, but for my home office (about 80% of my working hours) that would be enough. Alternatively, move into the children’s room for a few years.

I am allowed to take over my parents' apartment

That looks like a house?!? Is there a roof that could be converted? Where does the staircase lead? If you open up the kitchen, dining, and living room, a small work nook could be created.

Then plan the entire floor plan with an architect and structural engineer according to your needs. Otherwise, you have a problem cutting off 10sqm somewhere. Isn't a small desk in the hallway or bedroom enough? I don't know your needs, but for my home office (about 80% of my working time) I would be satisfied with that. Alternatively, move into the children's room for a few years.

Thank you for your answer. The office should definitely be a separate room, if only for tax reasons and (since I program) because I also need peace and quiet. I had asked an architect, he would move the door to the current hallway to the left, so that a narrow hallway to the hallway at the back is created next to the kitchen, and the current dining room becomes the new "office". But I am not completely satisfied with that.

That looks like a house, doesn't it?!?
Is there a roof that could be converted? Where does the staircase lead?
If you open the kitchen, dining and living room, a small work niche could be created.

Yes, that is a house, but the parents are already moving into the upper apartment. That's why I only have the lower one.
What do you mean by "open"? If I understand you correctly, that would be a work niche without a window, right? In any case, I need a separate room as an office.

I asked an architect, he would move the door to the current hallway to the left, so that a narrow hallway to the back hallway is created next to the kitchen and the current dining room becomes the new "office".
But I’m not completely satisfied with that.

If you look at the floor plan and your condition that you need a whole room, you have no alternative. You can’t get an additional room with this floor plan, only use the existing rooms differently. Basically eat or work, child or work, sleep or work.
The lesser evil: work in the bedroom.