how do i report a dead zone?

You could bring the lack of coverage in that area to the attention of Support.  Expecting things to change in a few weeks, if at all is unrealistic.  If it is the result of a tower that needs repair.  Dispatching people when there is a shortage of workers that maintain and repair cellular towers, especially during a pandemic, is going to take longer than normal.  If it is an actual dead zone.  Perhaps the issue why there is no service there yet, is because you mention it is a growing area.  Obtaining the site and permits to construct a new cellular tower and get it up and running all takes time.