Minimum door spacing during floor plan development

I think that also depends on the door frame chosen. There are certainly different dimensions regarding how far the wood extends outward.

That is 6 cm of remaining width in the door opening (in the shell construction, so still without the frame)

there is my question, what is the minimum [...] distance that must be maintained.

The approach of planning such minimum distances would lead to a house in which one would feel "optimal" tightness. Doors slammed into corners always reduce the perception of space even more than the actual space usage. Do you really want to create a house as an experience of discomfort (due to claustrophobia in every corner)?
A certain degree of exceeding minimum distances is essential for a house where one can live. Rooms are more than "closet compartments for inhabitants."

more than 90° is not necessary at least for us, as there is immediately a wall behind.

No matter what distance a cupboard follows then: to walk around it or past it, distance is still needed, otherwise the walking line has to detour.

We planned a distance of 12.5cm and that fits well, in an emergency about 6cm also works if space needs to be saved.

Best regards
Sabine

Just measured in our apartment, 1m door width (including frame), door leaf 86cm, distance to wall (drywall) 10cm/13cm. Opening angle > 90°

The approach of planning such minimal distances would lead to a house where one would experience "optimal" closeness. Doors slammed into corners always reduce the perception of space even more than they reduce the actual floor space. Do you really want to create a house as an experience of discomfort (due to claustrophobia in every corner)?

In some places, however, it sometimes cannot be helped (without having to make other compromises). I know this from our plan as well. A corridor as small as possible leads to narrow distances between two adjacent doors. Objectively, one has to decide between

a) close wall distance of the doors, but generous door widths,
b) generous wall distance of the doors, but smaller door widths,
c) enlargement of the corridor at the expense of living space in 3 other rooms.

We ended up with a). Therefore, I find the question quite interesting whether there are "normal" standard minimum distances in the raw construction dimension across different manufacturers.