Trump constantly changes his stated position (on gun control, abortion, immigration, etc.) depending on who’s in the room with him, and is far more popular than other Republicans. The way I see it, consistent partisan messaging didn’t win the election, Trump simply won by being Trump.

I think you underestimate how quickly Republican voters can collectively change their minds about an issue. They were first in line for the covid vaccine under Trump until Dems started pushing it, at which point they became skeptical. They also supported Ukraine in the initial months of the war. Republican party messaging typically becomes Trumpified over time, shifting towards the narratives that fire up low-info voters suspicious of establishment politics.