@Filoux

So a few things:

One, We only currently have a few Wi-Fi 7 Decos available: Deco BE95, BE85, and BE16000 - so if you are looking to add Wi-Fi 7 functionality to your home, you would need one of those models. But all Deco models can work together to create a mesh.

This means that your Wi-Fi 7 model will communicate with previous AC/AX/AXE models to create a mesh network - however, your connections between nodes will be limited by the S4s technical abilities. Any compatible devices connecting directly to the Wi-Fi 7 node will be able to take advantage of the tech, but beyond your main node, your devices will connect just as they always have.

As for the 'levels of network' that you mention, the closes thing is the fact that some features of your network are dependent on the model of your main Deco node - meaning you should always aim to have the main node be your most powerful, especially since all traffic will eventually need to pass through that node's processor. This will also avoid having your main node become a bottleneck for your entire network.

Very lastly, if you have been reliable using a Deco S4 mesh, you may consider a lesser upgrade to either the BE16000, or even to a Wi-Fi 6/6E network