Setting up Modem/Router to home network

I live in a rural area and our only options are satellite or fixed wireless. I setup my fixed wireless system using a WE826-T2. I have 2 Yagis and a tower and get great internet speed. However, the wireless capabilities of this device leave much to be desired. I get constant disconnects and the range is very limited. The cellular internet is stable and seems to work at all times (using my ethernet connected desktop). I already own a Netgear X6 with DD-WRT firmware. It has been running my WiFi for a couple years with no issues whatsoever. I really would like to just use the WR826-T2 as a modem only and connect my existing router to it with ethernet cable. It worked successfully the first day connecting to the lan port on the modem/router and the wan port on the Netgear. Now, for the last 3 days no matter how I connect the ethernet cable I cannot get internet through the Netgear router. I believe it may be the 2 routers not being able to work together although it worked the first day. I have the modem/router on and the Netgeat router is set to I have tried many different ranges and it still won't work. Again, there is internet available through the WE826-T2 at all times. Is there a way to setup the WE826-T2 to just act as a broadband modem would? So, I will be able to use my existing router setup? Thank you in advance. I did try lots of research, but didn't seem to be able to find anything that answers this issue.

Maybe this? And disable all routing functions (e.g: DHCP) on the WR826-T2 itself.

Thank you! That is exactly what I needed to get this working properly. Very much appreciated. Have a great day.