RBS40 very weak 5g wifi

What Firmware version is currently loaded?
What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

V2.5.1.22

I don't think the modem is related as the router is working fine. 

Is the RBS directly connected to the back of the RBR or is there a switch in between?
What is the Mfr and model# of the ethernet switch in the configuration?
https://kb.netgear.com/000051205/What-is-Ethernet-backhaul-and-how-do-I-set-it-up-on-my-Orbi-WiFi-Sy...

It is directly connect. I have a desktop connecting to the satellite via wire and it is working fine as well. The only issue is the weak 5G wifi 

What is the size of your home? Sq Ft?
What is the distance between the router and satellite(s)? 30 feet or more is recommended in between RBR and RBS to begin with depending upon building materials when wirelessly connected. https://kb.netgear.com/000036466/How-far-should-I-place-my-Orbi-satellite-from-my-Orbi-router

My home is only 400sq ft, yet there is a wall between my room and router so I have put a satallite in my room. Otherwise I can only get a very weak wifi signal from the router.

Are you next to the RBS when looking at the signal or at a distance? 

What does the RBRs connected clients web page show for connection status? 

Yes I am next to the RBS. 

In RBR it is showing fine with all devices connnected to satellite using 2.4G only. 

Tried using the settting remmended. Still got no luck on the 5G wifi. I could only receive a signal with -79dbm even if I am sitting next to the router. 

I wonder if anything I could use to test the satellite 5G signal alone.. otherwise I may need to go for warranty