If you have social media, try to get friends, neighbors and others to call, and post about it. Maybe have someone record the call and post that, or go directly to their studios and ask, while filming with your phone.
Expose them to the entire community.
Maybe go higher/above the news director. Also contact other news stations and newspapers in the area. See if they will report on the obvious unfair bias.
Would be really good if you knew an elderly person who does not have Cable, and only has local channels. Have them be the center of story, that they cannot watch the historic impeachment trial, because of this obvious bias. They played the entire Clinton impeachment in the past,
And as you said they covered the dems first few days.
This is a good example of Fake propaganda news. Make sure everyone in your community knows. If you can't trust them to be fair, you can't trust them to be a reliable source of news.
Maybe protest them. Would be glorious to see thousands protesting the news station, calling them out. People need to call these clowns out, and wake up hundreds/thousands in the process.
It's 2020, election is in 9 months, if you have proof/obvious bias, maybe you and the people in your community can make changes, get people fired.
Just a few suggestions to help you fren.