@WiCreekPaddler I am getting conflicting info from you. You said "The deco M5 is plugged into the modem directly. The other port on the deco M5 is plugged into my PC, which never has any issues" -...

@Xenomes >Ok had try that, do you recommend a satellite with the less devices? I would recommend Satellite that is not taxed with Ethernet traffic. Smart TV is 100Mbps link at most, very lightly...

@WiCreekPaddler OK, so this is not just "one out of four units" you have problem with, but Main Deco specifically. That fact will eliminate many theories and unnecessary troubleshooting. You do not...

@Xenomes This network diagram does not fit my theory of what might go wrong, so I am going to provide other troubleshooting recommendations and perhaps one of them will help: 1. Replace Ethernet...

@koswo An example of powerline adapters troubleshooting resource: https://www.amazon.ca/vdp/04e47249121748a081dbb46fb5a2bc2d

@koswo Get pair of standard powerline adapters like these: https://www.tp-link.com/us/home-networking/powerline/tl-pa7017-kit/ After you configure them and verified they provide access to your home...