The coverage range of the TP-Link RE550 depends on various factors, such as the architecture of the house, the presence of obstacles (walls, furniture, etc.) and interference from other devices. However, under optimal conditions (open spaces without obstacles), the TP-Link RE550 can extend Wi-Fi coverage up to about 100-150 metres. In indoor environments with obstacles, the actual distance could be reduced to 30-50 metres.

The question is not quite clear... but if you place the repeater in a place where you still have acceptable reception performance on your mobile, for example, then the repeater can still serve a room of 100m2 from this location.