Save and Restore Router Configuration

I have been on ATT Fiber for a little over a month. So far, I'm somewhat disappointed with the WIFI performance of my BGW320. So, I'm thinking I will put it into passthru mode and set up a mesh network with my ASUS routers. This will be a first for me and if I foul it up on the first pass, I would like to be able to restore my current settings on the BGW320. My ASUS routers give me the opportunity to save router config files to my computer and restore them if I foul anything up. Is there such an option on the ATT router?

Also, from some threads here I have gotten the feeling that the setup to a BGW320 in passthru mode will be less accessible than it currently is. How do I get to it? Must I have an ethernet connection directly into it? My original impression was that, in passthru, it shares an IP with only one device and that I could get through it via the mesh that will be serving wifi.

Thanks!

Gary