To answer your question, Sarah, I actually do think that losing control of the Senate will serve as a turning point in elected Republicans’ relationship with Trump. It will be aided by the fact that Trump also won’t be in Washington anymore and every tweet will no longer be newsworthy.
The past four years haven’t been particularly fun for many Trump-skeptic elected Republicans, and I’m sure they would like to get out from under his thumb. But Trump’s bully pulpit, the base’s enthusiasm for the man and the muddled 2020 results made it difficult for them to make a discreet argument for why the party should distance itself. The high-minded ideas of decorum and democratic norms weren’t really working/didn’t work in 2016.
Now, the Georgia runoffs are a discreet, dramatic, highly televised event that Republicans who wish to turn on Trump can use to greater effect than probably anything else during the Trump presidency. After all, nothing else matters if you can’t win.
(Btw, Trump knows this intimately, and that’s why he has launched such a campaign to convince voters he won. He likely knows he’s leaving, but his future power depends on whether the base sees him as a winner or loser.)