an arris xg1v4 box

My current main hub tv box is 7 yrs old and is eol. This is evidenced by the facts that it has trouble handling apps and its response time is getting much longer. I was informed that a new box would solve this. Due to the configuration in my home where there is a main hub box and a secondary non smart tv all connected with coaxial cable, my research indicated that an Arris xg1v4 would be the one to solve my problem. I have called 3 time and been to the local Comcast store once requesting this model and each time I have been given a device that was either incompatible with my configuration or just as slow or sluggish as the old one. Even Paramount plus has said that these other boxes don't work as well or are not compatible with their app. So how do I get this Arris xg1v4 box. I also like this model as it has internal storage as Im paying for 150 hours of storage. Im at my wits end as I cant see paying for a service that I cant watch