At&t uverse with Orbi

I have an Orbi router and two satellite system (box says RBK43S) and my ISP is At&t uverse which provides a cable modem/router combination box.  They do not allow it to be placed in "bridge" mode as Ive been told is required by Netgear support.  They do allow it to be set to passthrough however.  That has been done on our set-up, its in passthrough DHCPS-fixed mode with the MAC address of the Orbi router set-up.  

I have the Orbi router in my closet since that is where all the connections are, one satellite downstairs and one upstairs (4400 sq ft house).  Im constantly losing my wi-fi connection if not near the router and having to resync the satellites (mainly the upstairs) a few times a day.  We do have several devices connected at any one time (14 on average).  The Orbi is currently in router mode since AP mode did not work for what we need.

My questions:

- With the AT&T router in passthrough mode and Orbi in router mode, do I also need to turn off the 2.4 and 5.0 wifi via AT&T?  If so, what needs to be done after I go through that process?  Right now I have two wi-fi network options - the Orbi and the AT&T provided.  From what I understand this causes conflicts and performance issues.

- Is the passthrough mode mentioned above the correct option?

Thanks in advance for any guidance