@bgoyal 

Hi, thanks for posting question here.

Ideally, Archer AXE75 and Archer AX73 set up Easymesh network and they can handle 70 smart devices.

But it is really hard to say. For example, if all your 70 smart devices need to be connected to 2.4GHz wifi band, and your network environment is not that clean, the performance of some smart devices may be influenced. And usually, you may have other kinds of devices,which need to be connected to 2.4GHz/5GHz WiFi bands.