Should the garage be flush with the house or set back?

What exactly is a standard house with standard dimensions?

Standard would be the style of Town & Country or the Alto series from Heinz von Heiden. Floor area about 9x10 or similar. Or a city villa in 9x9 or 10x10.

Is that standardized somewhere?

No, of course not. But standardization in the house sector means what is compact and thereby cost-effective and energy-efficient, can be built simply and is thus functional and affordable for a family of four. It does not stand out with special features, but appeals to a large target group. Due to the standardization, the house is often pre-designed and sold as a type house. Often modules for individualization are also offered, for example Heinz von Heiden likes to extend the house lengthwise on the gable side, the Flair can for example simply be mirrored in half. Thus, the statics do not have to be changed, and the mason and carpenter build the house almost blindly. With a 9 meter house width you get two rooms that can usually be furnished well: a standard wardrobe is 60 cm deep, a mattress is 2 meters long and fits into a 2.20 meter bed. A simple standard master bedroom has space for a 3 meter long wardrobe and a double bed about 1.80/2.00 x 2.10. So with a room of 3 x 4 you can accommodate everything you usually need. 3 x 4, i.e. 12 sqm, is the standard size, even though many think that 10 sqm is enough or nothing below 15 sqm works. This way a house in the standard format fits well on flat plots that are often segmented and sold by municipalities in about 20-meter wide plots. Many counties have a minimum size for single-family houses, for example 650 sqm in our area. Therefore, one can say that almost all type houses fit these ideal dimensions of 20x30. A 140 sqm bungalow could already be tight in width at 20 meters. So if the house becomes narrower, e.g. 8 meters or less, you will already find some smaller difficulties in designing if you only think within the standard and are not willing to make compromises. Because then you leave the standard. But there are also narrower type houses, because the companies adapt to nowadays smaller standard plots, e.g. 20x20 or 16x25 (regionally dependent). Only then you do not necessarily have the standard floor plan that suggests itself with a 9x10 house.

Thank you very much for the detailed answer. Learned something new again

this is how it could look with a house 7.5m * 12 m.

Here with the attic as well.

if a project - as here - two purposes serves (garage AND privacy screen) that's great. But if disadvantages arise at the same time (less space), I would build the privacy screen differently. Such a thing doesn't need much space and there are many possibilities.

Here a similar width / similar problem and how we thought about it: Without garage.