Telus Wifi 6 Access Point Questions

"Presumably, that ethernet jack runs to the ONT located in a closet in another room." It should run to your router.

"I tried to adjust the Telus Access Point’s settings by logging into 182.168.1.254" 192.168.1.254 will log you into the router (you will need the credentials from the routing device to complete the login). Once there, you can find the IP address of the Wi-Fi 6 device (usually labeled Boost2.0 or similar) and connect using the credentials on the device. You can then seethe options of the Wi-Fi 6 device.

Yes you can use other AP devices, but you may have difficulty if you have Optik TV, as most Wi-Fi devices do not have the necessary Multicast signal needed for Optik.