Need help with ATT unlimited plan and Ipad USB Tethering

Hello, I have the ATT Ipad unlimited plan, I almost lost it like everybody else lol

I have since bought an ipad and jailbroke it and have PDANet running on it with the WiFi hotspot on, it is fast but the connection just keeps going up and down, I don't lose the IP address, but it stalls all the time, it will only download for a minute or more and then drop out and then pick back up usually under a minute, it's really annoying but useable for the most part.

I read about USB Tethering and thought that it might be more stable

I have a 3rd Gen Ipad on 7.1.2, an ASUS RT-AC1200 AC56U, and a Netgear AC1750 r6400v2 running DDWRT

I got DDWRT running on the Netgear but can't figure out how to get the USB tethering to work, from reading it looks like I might be able to get Openwrt to work on the Asus, not sure if it would work better than the DDWRT

Under WAN Connection Type - I have Iphone Tethering selected with the Ipad plugged into the USB3.0 slot

I can't find any guides or much info about what all settings need to be set or exactly what to do, most guides are for iphones, but none of those helped to get it working

Does anybody know what settings in the Netgear would need to be set to use the Ipad for tethering? or if it even supports it, it doesn't look like the Netgear r6400v2 is supported by Openwrt from what I read

Do I need a different router? would the Asus on Openwrt be better and have more options to work with the ipad?

Any help would be greatly appreciated, thanks