Looking for floor plan suggestions for a semi-detached house

Yes, the draft is already with the architect. It’s just fun to puzzle something out yourself.

I don’t see anywhere a space for a decent bedroom. Don’t you have a wardrobe? If your architect is a signatory with stamping authority, please make sure yourself that you find space for a proper wardrobe.
The stairs must also work for furniture: if you have to hoist the individual Ikea parts through the window into the upper floor, living there won’t be fun in the long run.
Toilets belong one above the other – here it makes sense to swap bedroom and bathroom (at least the location of the bathroom) so that the waste pipe remains in a corner. 10 sqm for the bathroom should be enough – otherwise avoid the T-solution, which takes up a lot of space from the room.
Place the toilet in the guest WC on the outer wall so that the pipe goes outside via the shortest route.

move the middle wall 20 cm further east - 3.5 m width for a bedroom is borderline, but might work. However, you still won't have a closet. The calculations are not correct - the bathroom currently has over 13 m², not 10.5 m². 8 m² for the bathroom is sufficient - rather try to find space for a closet...

I don’t see any space for a decent bedroom anywhere. Don’t you have a wardrobe? If your architect is a signatory with stamping authority, please make sure yourselves that you find space for a proper wardrobe.
The stairs must also work for furniture: if you have to hoist the individual Ikea parts through the window into the upper floor, living won’t be enjoyable in the long run.
Toilets should ideally be aligned vertically – here it makes sense to swap the bedroom with the bathroom (at least the bathroom’s location), so that the downpipe stays in one corner. 10 sqm for the bathroom should be enough – otherwise skip the T-solution, it takes up a lot of space in the room.
Place the toilet in the guest WC on the exterior wall so the pipe can go the shortest way outside.

The wardrobe is in the office. We have it like that now, and we want it that way again.
The stairs are the problem with the whole thing... if they are wider, the living area becomes too narrow. If the stairs are longer, the bedroom becomes too small. If I move the stairs more to the south, the office/dressing room gets smaller.
I know it’s hard to understand, but we really only use the bedroom for sleeping. In at night… out in the morning. So the minimum amount of space really suffices! We have it like that now, and we want it like that again.
The utility room, bathroom, and toilet are ideally situated together in my opinion... no long routes upstairs and in the attic for the sanitary lines. On the ground floor it would be even better if the kitchen directly adjoined the utility room, but there is too little light there. We only sit on the couch in the evenings anyway, so we don’t need daylight.
If we swap bathroom and bedroom, we’d have a roof window in the bedroom, which is a no-go. Also, on the north side there is a sloping roof with a knee wall of just under 1m on the upper floor.
The bathroom would be too small. The 10 sqm is not correct. Living area between 1 and 2 meters high counts only 50%.
I am happy to skip the T-solution… was just an idea.

Of course, I haven’t considered the pipes and electrical lines, nor the statics. That will be optimization work for the architect.
Hopefully, it’s solvable.

I have changed something again. The staircase is now inside and the kitchen on the other side. The wardrobe is built under the stairs. There is another guest wardrobe opposite. Positive: the solution utility room - entrance area - guest WC. Also a better interaction kitchen<->living area. What I don’t like so much yet is the utility room, you do lose space inside where there is no storage area. The staircase could become a bit dark. When you enter the living room you first look at the shelf. The upper floor is divided into 3 rooms: south side children’s room, north side parents’ room (including dressing room and office) and behind the staircase the bathroom. Probably a dormer on the north side makes sense. Overall, however, I have the feeling that this solution has advantages compared to the other design.

yuck no daylight in the bathroom ... too bad. That is a no-go

I changed something again.

... and in doing so completely lost sight of the upper floor...

The wardrobe is in the office. We have it like this now, we want it like that again.

Yep, but times can change, second child or sale of the property for whatever reasons: then you also have to think conservatively and find a middle ground between individuality and standard. We used to have the wardrobe in the office as well (that was initially an emergency solution), because the bedroom had a deficiency in terms of a normal 3-meter wardrobe. Later we found that good. Now in the new house we have a separate dressing room, but made sure that a common wardrobe fits in the bedroom - it might be that the time comes to turn the dressing room into an office, then you need wardrobe space in the bedroom again.

Greetings Yvonne