60 HZ verses 120HZ new TCL TV with Streaming Box

Hello, We just got a new TCL 4K Google TV 55QM7 - 120HZ/144HZ for our bedroom. My husband knows more about it but he said when he goes to Direct TV Stream which is hooked up to the correct HDMI we have the box he sees it pop up in the top corner 60HZ. I think the 144 is more for gaming but their are 2 HDMI's that offer 2.1 and it's plugged in to the right one. He said maybe the box doesn't support 120HZ or our HDMI cable isn't a 2.1. I just thought I would ask here. Thanks!