Feng shui issues. There is a 4-story multi-story building with an 11-story small high-rise with double the distance between the buildings to the south. Does it count as a block?

Absolutely blocked. The current distance between buildings is calculated as 1.3H. That is, if the building on the south side blocks the north-facing building, the distance between buildings is 1.3 times the height of the building on the south side. Assuming that the floor height is 3 meters, then the building on the south side has 11 floors. That is 33 meters, and the distance between buildings is 42.9 meters, so... when you talk about the distance between buildings, what do you mean?