If att will allow, get an arris DOCSUS 3. 1 cable modem, model sb8200. Then pick up an Orbi RBK53 mesh router. You can sometimes find the Orbi in the Costco store on sale. If you can’t swap the modem, disable the ATT router part and still get the Orbi. Also, turn on Orbi Armor, it’s a subscription you turn on inside the router. This is a whole house firewall, especially good for us smarthome users.