One stumbling block that has plagued the MAGA movement in general, and Trump in particular, are those Trump supporters who ape Trump’s negative affect, but lack his comedic genius.
He uses biting humor to make his points, but that takes both timing and wit. Lacking either of those things, a small subset act as repellents for potential voters who might like Trumps policies, but who don’t want to be associated with the red faced weirdos.
Republicans already have a difficult time winning elections, when you piss off even a small percentage of potential voters it can mean the difference between winning and losing