Kitchen problem - Floor plan single-family house 150m²

Island in the small tubular space with a small sliding door won’t work.
And more free space between the lines is impractical. Line spacing should be around 1.2m +/- . The dining areas in the kitchen complicate everything.

For me, it will always look like an existing house.

Okay, so you mean that the line spacing only feels narrow, or oppressive because of the cabinets?

Maybe it isn’t actually that narrow... I would somehow find it nice if you had a wider kitchen entrance so the space looks bigger and then when it goes toward the workspace the space gets narrower. It’s just the question to what extent you could get something like that out of this floor plan.
As it is currently, it’s definitely bad.

Well, square meters are quite relative when it comes to a kitchen. Together with the requirement that it has to be a closed kitchen (I will never understand that when children are planned, but of course, that's subjective), it's really difficult with these dimensions. I would make the window by the sink floor-to-ceiling and 1.10m wide, and then narrow the room so that it really becomes two rows. You have to decide on the door. If open might still be an option, you could consider separating the dining area and the kitchen only with a counter or island and have the access run through the hallway.

Well, square meters are relative when it comes to a kitchen. Together with the requirement that it must be a closed kitchen (which I will never understand if children are planned, but of course that is subjective), these measurements are really difficult. I would make the window by the sink floor-to-ceiling and 1.10m wide and then narrow the room so that there are really two rows. You have to decide about the door. If open might still be an option, one could consider separating the dining area and the kitchen only with a counter or island and have the access run through the hallway.

The advantages of both a closed kitchen and an open kitchen are known and obvious. For us, the advantages of a closed kitchen outweigh those of an open one; therefore, an open kitchen will not be an option. I suspect that if we plan such a solution with a window, we will have too little workspace and storage possibilities.

The corner cabinet variant is just very old-fashioned. I think Saralina87's suggestion is really right for the room and corresponds to my proposal a few posts earlier in terms of the row layout. The light strip is really rubbish there. I believe you are still in an early planning stage. I would fundamentally think about how I want my kitchen to look and then plan the house "around it." For me, a kitchen is important, but that doesn't have to be the case for everyone. But your kitchen is just a "byproduct" of the rest of the floor plan. The leftover stub is simply appointed as the kitchen.

Then you will have to accept that with these room dimensions and this door position, there are hardly any other fundamental possibilities to design a kitchen. The positioning of the tall cabinets can certainly still be debated, but not much more is possible.

You have already seen yourself that the tall corner cabinet doesn’t make any sense. If you line up the refrigerator (?) with the row of tall cabinets, you would have space for a wider sliding door. I think the window by the sink is fine as it is. What bothers me more is the window at the small seating area. Why does it have such a high sill, is the seating area even desired and necessary? Instead of that, you could also plan additional base cabinets and then have one less tall cabinet. The width of the kitchen itself is not that small as far as can be seen.