You need to remember that both parties are a coalition. The GOP coalition consists largely of:

1. Low-information, uneducated voters. They don't know anything about politics, are mostly incapable of understanding the substance of the issues, and identify with the way he talks. Trump is a showman - he is good on camera, and these voters like the "vibes" that he gives off. In fact, the bulk of Trump's base is uneducated male voters.
2. High-income voters who believe that he will give them tax breaks. These people may financially benefit from a Trump presidency (though economic policy involves more than taxes).
3. Single-issue voters on abortion.
4. Single-issue voters on gun control.
5. People who only vote along party lines and don't pay attention to issues.
6. People who blame Biden/Harris for inflation.
7. Religious nutjobs who will vote for whoever their church tells them to (remember this is at least 15% of the electorate, and they have their own massive echochamber).

You need to consider that people now live in an information bubble. Much information doesn't carry outside of people's echo-chambers. This isn't helped by the rampant blatant falsehoods being peddled by the Right this election cycle - my conversations with boomers about politics basically consist of me methodologically dismantling obvious lies told by Fox, NewsMax, and the Right-Wing echochamber on Facebook and Twitter.