Ethernet Backhaul Issues

What FW version is loaded on the Orbi system?

How is the switches connected and how are the RBS connected? 
Is the Switches directly behind the RBR then RBS connected to the switches? 

What CAT# LAN cable are you using? CAT6A STP is recommended. 

How RBS should be ethernet connected to the RBR with a switch in the middle:

https://kb.netgear.com/000051205/What-is-Ethernet-backhaul-and-how-do-I-set-it-up-on-my-Orbi-WiFi-System📡 ‌‌🛰️

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 wired or wirelessly connected.

The 960 series is 2.5Gb LAN port supporting, you might consider checking into a mutli GB non managed switch, something past 1Gb. 

What channel configurations are currently set on the router?

Your ISP Modem already has a built in router and wifi. This would be a double NAT (two router) condition which isn't recommended. https://kb.netgear.com/30186/What-is-Double-NAT

https://kb.netgear.com/30187/How-to-fix-issues-with-Double-NAT

Couple of options,

1. Configure the modem for transparent bridge or modem only mode. Then use the Orbi router in router mode. You'll need to contact the ISP for help and information in regards to the modem being bridged correctly.

2. If you can't bridge the modem, disable ALL wifi radios on the modem, configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the Orbi router gets from the modem. Then you can use the Orbi router in Router mode.

3. Or disable all wifi radios on the modem and connect the Orbi router to the modem, configure AP mode on the Orbi router.

Static IP Address Configuration for AP Mode | NETGEAR Communities

https://kb.netgear.com/31218/How-do-I-configure-my-Orbi-router-to-act-as-an-access-point

and https://www.youtube.com/watch?v=H7LOcJ8GdDo&app=desktop

Try option #2 first...