Now of wall between router and satellite?

Wi-Fi doesn't pass through concrete very well.  Moreover, Wi-Fi signal strength is regulated by the government, and all higher-end routers should all be at or near those limits.  It's unlikely the Orbi will work.  You need to run a wired connection (Ethernet, MoCA or Powerline) for best results.

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Vobuai wrote:

I have s small flat (less than 1000 sq.feet) but with many bedroom. The distance between router and the far bedroom (where I am going to place the satellite) is less than 20m but was separated by 4 concrete wall. Normal wifi doesn't work (most of the time totally no signal at the far bedroom), may I know if Orbi able to work prefectly in this situation?

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so the idea of the orbi is to get the transmission closer to where its needed

you place the orbi router where you normally have your internet connection and you then place the sat prob in the hall down near the bedrooms , if you can do this and the hallway normally get a wifi signal you may find the orbi sat then pushes the signal into the bedrooms through the doors

so yes it may work better that what you have tried before but the only way to correctly answer the question is to put the orbi system in place and see how it goes and return if it doesnt perform well