@David-TP 

Hello and thanks for the reply. Unfortunately not, there is too much distance. The problem is that this connection sometimes works well and the Deco on the upper floor connects to the closest one, sometimes badly and connects to the main one,

probably depends on whether or not I open the door of the room where the main one is located.

 Maybe I should space the main one more or make it come out "less powerful"...according to Is there a possibility of doing this or finding a suitable device?

tx 

  @David-TP 

for example, if I replace the deco s7 upstairs with a TP-Link Deco M5 would I then have the option to choose?

Thanks and sorry if I'm bothering you