Change settings to WPA3

First do you have a majority of Wi-Fi WPA-3 enabled devices?

The AT&T BGW320 Gateway's don't currently support a WPA-3 only configuration. They do support WPA-2 and WPA-3 concurrently which would be considered transitional state.

Very easy to set in the Gateways' just navigate to the Advanced Options link in the Admin Interface:

1. 192.168.1.254

2. Select Home Network link

3. Select Wi-Fi link

4. Select Advanced Options link

5. Select the Wi-Fi mode for 2.4 GHz and or 5GHz as appropriate

6. Click the "Save" button

ETA: Still leaning to type...

Dave

If you have a BGW210, acquire your own router or access point that supports WPA3 security and replace the Wi-Fi feature of the AT&T Gateway with it.  The BGW210 doesn't support WPA3.  However, the BGW320 does, per the following posts by dave006.

If you could change it, it would be on Home Network > Wi-Fi > Advanced Settings...   However, right now I only see choices of WPA2, WPA1, and WPA2+WPA1

As far as I can tell, none of the current versions of firmware for any AT&T Gateway support WPA3.

The BGW320 Gateways support WP3 in transition mode which means WPA-2 and WPA-3 with the current Firmware level of 4.25.4

If you could change it, it would be on Home Network > Wi-Fi > Advanced Settings...   However, right now I only see choices of WPA2, WPA1, and WPA2+WPA1

WPA-1 and WPA2, WPA2 and WPA-2 and WPA-3

Dave

I shouldn't assume that the BGW210 has the same capabilities in Wi-Fi that the BGW320 does, especially since the BGW320 has Wi-Fi6.

Okay, a BGW210 cannot do WPA3.  I fixed my earlier post.  Thanks @dave006 

Acquire your own router or access point that supports WPA3 security and replace the Wi-Fi feature of the AT&T Gateway with it. 

@JefferMC 

Even third-party routers have issues with full WPA-3 Only mode and the multitude of client to support without issue with issues with performance with authentication and encryption. WPA-2 and WPA-3 mode provides compatibility for WPA-3 devices to connect without the need to impact the majority of WPA2 devices.

Dave