There's so much to talk about when talking about the rise of Trump. It would take 100 pages to cover it all. Social media played a big role, but I'm not going to get into that.
In general, I think people saw things happening that scared them. If you were concerned about illegal border crossings, you're a labeled a racist. If you are against affirmative action, you're a racist. As part of wokeness, people were losing their jobs for what was essentially thought crimes or because they were white and dressed up as a black celebrity 20 years ago. There were censorship and free speech concerns and there was no faith in the current Republican party or it's politicians to address the issue. We had just come off of the Romney/Obama election... two guys who were, politically, about as close to being the same as any two politicians ever in the Presidential race.
Along come Trump. He doesn't talk like politicians. He talks like "we" talk. He doesn't sugar coat it. He talks straight about the things that worry people.... and so it began.
In the eyes of Republican, and many undecided voters, things haven't gotten any better. Wokeness and cancel culture are largely gone, but in its place is drag queen story hour, DEI, people losing their jobs for saying "all lives matter", cops standing by while businesses are looted. Minnesota politicians calling it a "priviledge" to be able to call the police for help when their house is being robbed and calling or the complete elemination of police. CNN broadcasters standing in front of burning buildings saying idiotic things like "It's a fiery but otherwise peaceful protest". In some cases, people being fired from their job because of something their spouse posted on line. Then there's the lie of a stolen election that consumed the country. Now, you have the economy and inflation and gas prices combined with a very, IMO, underwhelming Kamala Harris.
Again, there's a significant underlying social media influence here.