I think there's a bit of a confusion here. McConnell will not vote in the impeachment vote in the House. He's not there, he's in Congress. It's a near certainty that Trump will be impeached in the House, but this is just a statistical fact and doesn't change anything really. He will not be removed (neither by invoking the 25th amendment, nor by removal from the Senate which requires a 2/3 majority.) and there's nothing that stops him from announcing that he will run again.

The Dems don't have the time to push this through the Senate for removal and even if they did have the time I'm pretty certain McConnell would have blocked it. Pelosi is achieving nothing really, Trump will have the badge of 2nd impeachment, but so what?

Pursue the guy in courts for tax fraud, that's how they will make him irrelevant.