Gl-ar750 dhcp

does this process work for enabling the x750v2 as a secondary internet for my dual WAN router?

I have a router that primary WAN is a cable modem and want to use the x750 as a WAN failover but when it does fail over I don’t want it to interfere with DNS etc.

Essentially I just want to use the x750 as an IP passthrough from the cellular modem in the x750