There's some more discussion of recent polls here. https://fivethirtyeight.com/features...trump-approval
While there's been a significant fall, around 2/3 to 3/4 of those identifying as Republicans still approve of Trump. A similar proportion of those approving say they strongly approve. So it looks like the majority of Republican voters are still pretty strong fans of Trump. Therein lies the problem for saner Republicans wanting to take back control of the party.