AX6000 Orbi RBK853 wifi disconnects

Hi there 🙂

I'm at the point where im almost pulling out my hair haha

My setup is as follows:

Network Terminating Unit - supplied by ISP (CABLE)

My personal router - D-link DSR 1000AC

Orbi connects to the above router LAN port 1

Orbi setup went smooth but then realised WIFI was dropping in and out. I was watching my phone as I was sitting next to one of the satellite speakers and could see the signal drop by half, then disappear and then my phone would switch to 4g. Sometimes its stable for an hour or two then i see it dropping in and out again.

I have been in touch with support who suggested changing the channels and MTU etc but nothing has fixed this. The firmware is up to date.

I also ruled out my personal router as being the issue by removing it and setting ORBI up as the main router. That also worked fine but could then found WIFI signal was still dropping out on the satellites. The WIFI from the main ORBI router seemed stable as far as I could tell. 

Any other tests I can do here. Is there a way to tell which router/satellites are dropping out?