Terrace door: Maximum functional width?

correct looks even somewhat symmetrical from the outside,

Ah yes, that looks very successful. The house too Is that in the basement just a support during construction, or is the permanent support in the corner window really that slim?

Insulation and plastic cladding have meanwhile been added around it. The support is necessary for the statics because of the corner window and there is not enough space for bricks.

Are there any other suggestions regarding the arrangement of the windows?

If we move the sliding door to the dining area, wouldn’t it look oddly arranged from the outside?

Or is the current plan impractical?

that's a sliding door, right? In this case, there is no maximum width because it is fixed in the frame and not hanging on pivot-tilt bolts. I also find the sizes and positions okay as they are.

I would make the two single patio doors at the dining and couch areas fixed elements. No one will ever go through there, except the burglar.

We also have the kitchen window like that with an island in front. We made the island with 40cm cabinets on both sides, so the "bar" is 80cm thick and the countertop runs continuously as a windowsill. The window has a fixed lower part of about 30 cm, the upper part of the window can be opened. This way, you can also place bottles or herbs in front of the window and don’t always have to put them away.

Upstairs you have French balconies. Alternatively, there are also windows here with a fixed lower part. But this is an absolute optical matter of preference; sometimes I like the French balconies better (it doesn't look so bare), sometimes it looks like prison... depends on the day (we have a fixed part, you can display something for (children) there).

I can't help you with the windows, but I noticed something else: I can't find a sink in the bathroom on the upper floor.

I would make the two individual terrace doors by the dining area and couch as fixed elements.
No one will ever go through there, except the burglar.

We thought that we might also be able to leave the left one (in the sofa corner area) tilted open for ventilation occasionally. Later on, we could possibly buy an insertable fly screen for it.

We have the kitchen window like that too, with a peninsula in front.
We built the peninsula with 40cm cabinets on both sides so that the "counter" is 80cm thick and the worktop runs continuously as the windowsill.
The window has a fixed lower part of about 30 cm; the upper part of the window can be opened. This way, you can also place bottles or herbs in front of the window and don’t always have to put them away.

That’s how we had planned it too, nice to hear it worked well for you.

Upstairs, you have French balconies.
Alternatively, there are also windows here with a fixed lower part. But it’s really an aesthetic question of preference; sometimes I like the French balconies better (doesn't look so bare), sometimes it looks like a prison... depends on the day (we have fixed parts, you can imagine something on it (for kids)).

We were also undecided about this for a long time. But this way cleaning the panes is a bit easier later. Ultimately, we like both.

I can't help you with the windows, but I noticed something else: I don’t see a sink in the bathroom upstairs.

The draftsman completely forgot that; it’s already on our list of changes. Thank you very much!