Second thoughts on the sale agreed price

Generally the more building there is an area is indicative of high demand, so counterintuitively, purchase values tend not to be impacted.
A higher percentage of apartments are bought by investors (historically typically 70%) so apartments rather than houses tend to have a greater downward pressure on rental prices. But not likely to impact your home value if you are in a house.
In my own experience, a 6 floor structure was built about 20m away from my last home, to the north. Honestly once the painful process of them building it was done, I barely noticed.