@gmoney63 In Main Building you will need to connect Deco X20 to TP-Link Archer with Ethernet cable. Deco X20 will not communicate wirelessly with TP-Link Archer router. In Out-Building-2 Decos will...

@Barel Too bad you can't use MoCA, it works very well. Your two options are exactly as you outlined them: powerline adapters or Satellite Deco X50 to which PC will be connected by Ethernet cable....

@Barel There may be one more option. You said you had cable Internet with cable box near PC. It means, you have TV cable terminating near PC. If other end of this TV cable is near X50 Pod, you can...

@David-TP Just want to point that this is not just Brazil. I am in Canada, I lost ability to enable Guest Network without password, which I had before.

@rcoan As others have found, password requirement is enforced by Deco app, not by X50 firmware. It used to be that Guest Network didn't require password at all. If you can find install file of older...

@John_Reading In Deco app it should show connection type for Satellite Deco. In example below Bedroom Deco connects by WiFi, Office Deco connects by Ethernet: