Except the worm can’t turn. The Republicans have become so routinely horrible that they can’t credibly threaten to be worse.
If the Republicans gain a majority in two years, will they try to impeach Biden if the Trump impeachment goes through? Yes.
If the Republicans gain a majority in two years, will they try to impeach Biden if the Democrats drop the Trump impeachment? Also yes.
There’s nothing the Democrats can do that will put the Republicans on their good behavior. The Democrats shouldn’t try to make deals with the Republicans because the Republicans aren’t capable of making a deal.
We should treat Republicans like zombies. Don’t try to reason with them. Don’t try to negotiate with them. Don’t try to meet them halfway. Don’t try to appeal to their better nature. Just recognize them for what they are and defend yourself against them.