If I iselect deco unit with best signal in that search list and finalize the configuration it says that it is unable to connect. Adjust macOS settings for internet sharing, and in a few clicks, you will turn your old computer into a Wi-Fi hotspot.

Connect your old iMac or MacBook to the Ethernet and place it where you need to access the Wi-Fi signal.

This is handy if you often use a wired connection. I also tried to connect extender to my laptop through ethernet connection and manual configuration but first thing during network search it finds deco wifi network SSID but all deco units mac addresses are listed with last Hex block of MAC address set to what's reported by deco app + 2 (for example 98 instead of 96 or B8 instead of B6) is that normal ? No problem reuse your old Mac as a router or a signal extender. With the Connectify Hotspot software, your computer becomes the best WiFi range extender. Choose the connection that you want to share. This will be located in the left sidebar. This is the gear-shaped icon just above the power icon. Using WPS doesn't work (on deco app WPS timer gets checked and disappears) but on extender side unit remains on flashing green led for wifi signal Forget about shopping for WiFi extender devices to boost signal. This is the button shaped like the Windows logo in the bottom-left corner of your screen. I also found an old Tplink Range extender WA860RE (V1 hardware but latest firmware avail 3.15) but unlike what is mentioned in that thread I'm unable to connect it to the wifi network managed by the Deco. Have a deco M5 wifi network with 3 units (working just fine and all units with latest 1.4.2 firmware)

Use mac as hotspot extender