One thing I have consistently noticed in every election since 2020 is that the early mail-in voting is a massive advantage for Democrats in every state.
When the early vote results come in, it's something like 88%-11% in favor of the Democrat. This means on election day, Republicans are playing catch up, and it's hard to beat 3 months of voting with one day.
It seems Donald Trump has trained the GOP base to believe voting by mail is akin to committing a crime, or "voter fraud". This is clearly a severe hamper on their chances of winning. Trump has managed to voter suppress the Republican base.
Why are they still so averse to voting by mail?
Republicans are unable to come to terms with the possibility they can be wrong, let alone actually admit they were wrong. It's the sort of brittleness that comes from building everthing on lies - nothing can ever be questioned, because it all might come tumbling down.