Orbi - mobile connection

Hi I bought an orbi 40. I use the router under the stairs as that’s where the fiberoptic point is and the satellite not that far away in the living room for the PlayStation etc. I have 120mb broadband and currently getting about 110mb on the satellite so really happy with that, however when on our mobile phone although the internet might be 90mbs Facebook ad instagram are really slow to load. I’m wondering if it’s because the Wi-fi is flicking between the router and the satellite and loosing connection. All my other Wi-fi appliances seem to work well? An ideas?

Cheers

Dave