It has nothing to do with the upstairs and downstairs of the building, because there are people living in the sun upstairs and downstairs, so it doesn't matter if the sun is full. If it is a bungalow or the first floor of a building, it will not be very good. Digging a cellar under the bed will affect the health of family members, and there will be strange things and diseases, because this is a place where yin qi is concentrated and the yin qi is too heavy. I don't recommend digging a cellar under the bed.
The above are personal opinions for reference and study.
I wish you all the best,
Yishanliangdong