@Diabl0 

Hi, Nice to see you again.

I believe you have viewed the post here already- WAN/LAN auto-sensing.

So in brief, WAN/LAN Auto-sensing will not make the whole network useless, at least for the wireless network and the Ethernet connections from satellite units. It has been explained WAN port-switching was only triggered when the ISP network went down. As long as the ISP network recovered, the issue was no longer here. If you don't want to wait for ISP, you could also connect the wired equipment behind the main Deco to one of the satellite Deco units, or put Deco into the Access Point mode if there is an ISP router in the front.

We do plan to support a static WAN port on Deco and Deco X50/X50_V1 is the first model which has supported this feature. 

The WAN/LAN auto-sensing technique has long been one of the fundamental protocols of Deco. The decision to change it was greatly influenced by community feedback. So all your efforts here must be acknowledged. However, the rollout to different models will take time and patience.

Thank you very much and best regards.