Hello@Francois_Deco ,

Welcome to our community!

According to Google Translate, your question is that if you can use 2 Deco X50 units to cover your whole home network. If there is any discrepancy, please describe it in English.

From your description, it seems your proposed topology is: router + main deco (1st floor) -- RJ45 port -- satellite deco (2nd floor).
This is feasible. To avoid double NAT, you can switch the deco network to access point mode. How to set up Deco to work in Access Point mode

Even if your router's signal already fully covers the first floor, you could consider adding just one wired device, such as an access point, or a single deco unit, a single router, or other network device to expand the network via wired connections.

Thanks.

Hello@Francois_Deco ,

Thanks for getting back to me.

Deco routers don't necessarily outperform traditional routers, as performance is primarily determined by specifications.
If you're looking to cover a terrace (outdoors?), consider the Deco X50-outdoor.
For the second floor, you can still choose the Deco X50.

Best Regards.