I assume you also see this on pre-recorded programs. TV news coverage is often done with a mix of cameras that often are not as good.
I didn't see a significant loss of qualtiy before I shut down my Verizon service in NY last November. Now a Frontier (former Verizon) customer in Florida.
Does the TV have more than 1 HDMI input?
If so, have you tried swapping?
Do you have another STB/TV? If so, have you tried swapping boxes around?
Just trying to determine if it is box or TV?
I have had problems with TVs where an input port starts going bad.