Exactly for that reason. The Democrats want to get rid of him but if the Republicans impeach him for something other than cognitive decline(i.e corruption and bribery) the Rats are forced to defend him for the duration. Dont let them control how everything happens. That’s how you lose.
The danger of that strategy is it may push Dems over the edge—and they might refuse to defend him and instead hasten their efforts to get rid of him.