For example on wikipedia for Switzerland it says the country has an area of 41,285 km². Does this take into account that a lot of that area is actually angled at a steep inclination, thus the actual surface area is in effect larger than what you would expect when looking onto a map in satellite view?
Doubt it. Because then it becomes a question of resolution, where too high results in countries with infinite area, since ever slope, ditch, and grain of sand has to be accounted for.
That also applies to calculating the flat area though.
https://en.wikipedia.org/wiki/Coastline_paradox
Luckily while the coastline number is affected, the actual area is still bounded. It’s like that infinite horn with paint paradox.