Perhaps it's something as simple as some folks not liking Trump, but still adhered to the republican philosophy, hence their vote for Biden, then voting GOP down ballot.

That can't be it, because essentially there IS no Republican philosophy any more. What? They trust Putin over US Intelligence agencies? Think the US should forego democracy? Even if they were traditional Republicans, the Trump Party candidates they voted for are not traditional Republicans any more!

They just have not figured that out yet. Their votes were mostly habit and momentum.

We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.