Thank you all for the info. Actually I have read Everything Xbee post already and am trying to order Xbee 3 to enhance my zigbee network and show a network map with XCTU software. I have downloaded XCTU software already but it needs a xbee device been connected to show the network map.
If you read that post, it says sylvania plug can route around 6 devices, while Xbee 3 could route 12-20 devices. Seems have to have xbee 3 to visualize my current zigbee network. Currently, I can see signal for my Xiaomi devices is around -60 dbm ~ -90 dbm . not sure with xbee3 /sylvania added in, how could improve...