I think you’re both right.
Because the Trump admin had not had time to clean up voter/election fraud, they figured they’d lose the House, but the Senate was imperative to hold, so focus was on that. Plus so many weak sister/dirty Rs quit or “retired” that it was more or less inevitable that Dems would win.
But since the Senate held (and gained a few seats), Trump people knew that whatever criminal insanity the House tried would not be voted on by the Senate, or passed if voted on. So therefore the House could have its fits and insanity and nothing would come of it, with the plus that they would go pedal to the metal hog wild and show the world without a doubt with evil pieces of s*** they are. This has caused many regular Dem voters to leave the paryt.
Good points J - regarding the long term, overall plan, seems that one phase was getting the RINOs to quit, retire or get beaten by the RATS. So if we take it back next time there will be a whole new breed of Republican in there.