"We’re going to have to fight much harder and Mike Pence is going to have to come through for us. If he doesn’t, that will be a sad day for our country because you’re sworn to uphold our constitution. Now it is up to Congress to confront this egregious assault on our democracy. After this, we’re going to walk down and I’ll be there with you. We’re going to walk down. We’re going to walk down any one you want, but I think right here. We’re going walk down to the Capitol, and we’re going to cheer on our brave senators, and congressmen and women. We’re probably not going to be cheering so much for some of them because you’ll never take back our country with weakness. You have to show strength, and you have to be strong."

The word "fight" is in the transcript 20 times from Trump, plus the crowd chanting "Fight for Trump!" which he does nothing to dispel at that moment.

He never said to "kill Congress" or explicitly told his fans to fight. He also told the Proud Boys to "stand back and stand by" rather than standing down. He likes to play these kinds of plausible deniability word games so that you can say he never said something while the most extreme fans can connect the dots as they see fit. It's a game to him, because he doesn't understand that a President's words matter or that telling the truth is importnat. Words are just a tool to get what he wants at a particular moment.