Packet Loss and Gaming Issues With New XB8 Modem

Hello! 
Around a month ago, we switched from an XB7 to a new XB8. It was included in a bundle when I upgraded our TV box. There were no issues with the XB7, but I thought I might as well have the XB8 installed since it's the latest modem. Ever since then, gaming has been rough. High ping, packet loss, you name it. I tried unplugging the modem and coax cable and plugging it back in, I tried setting up a port forward (I read somewhere that it would help, but I think they were mistaken). It's just been frustrating. At first, I thought I should wait it out, just to see if it sorted itself out after a week or two. When that failed, I tried to take it into my own hands and look up ways to fix it. I am at a loss, and any help would be appreciated. The modem is exactly where the old one was, and the old one worked fine in that spot. Every other device in the house works fine as far as I can tell, it's just my PlayStation 5 having the issues.  As I said, any help would be appreciated. Thank you for taking the time to help.