MR60 Mesh Wfi 6 Router with 2 satelites

You can use the usual tools to get help on how to put the AT&T modem into bridge mode:

at t modem router bgw320 500 bridge mode - Google Search

There are several hits there that should take you through the process.

This is a more generic option:

at t modem router bridge mode - Google Search

The good news is that AT&T, unlike some ISPs, does not try to block this option.

In your case, it isn't just a case of avoiding conflicts between router and modem/router. You need to check that this move would allow everything else to work as you want. So you may have to do a bit of experimenting to ensure that the router can still connect to the office network and that you get the performance that you expect, and have paid for.

You have nothing to lose by playing around. You can always change to a different approach, putting the MR60 into AP mode for example.

An important thing to remember is that when playing around, you need to restart stuff in the correct order:

Be sure to restart your network in this sequence:

• Turn off and unplug modem.
• Turn off router and computers.
• Plug in and turn on modem. Wait 2 minutes for it to connect.
• Turn on the router and wait 2 minutes for it to connect.
• Turn on computers and rest of network.

Just another user with time on their hands.