Is a bungalow possible on a slope of around 20%?

The adjacent plot is not yet developed - therefore it is also difficult to estimate. The plot northwest (across the street) has just been sold. Due to the contour lines, they are clearly located at a higher elevation, so we wouldn’t stand out if filling was done. An on-site appointment is probably next - but nothing will happen before the end of April (as mentioned, about 5 hours travel time). I will definitely consider the option of a basement (I prefer to have more options anyway): due to the significant slope, a basement would perfectly elevate the bungalow. Consequently, there would be no need for disposal of excess excavation, but probably no need to bring in fill material either. I’m curious about the calculation regarding the basement. After all, we want to have an area of around 160 m2 in the bungalow (excluding garage/carport).