I definitely think COVID was a big part of it.
I loudly said so at the time. I took an enormous amount of shit for saying that it is “just the flu” and “let it rip” was a fatal mistake. The descent of the Right into Alex Jones-tier conspiracy theories and crankish, do nothing libertarianism was the actual terrible optics that alienated White college-educated, moderate suburban voters. It sealed Trump’s image as a moron with Independent voters.
In the end though, Joe Biden was always ahead in the popular vote and he ended up winning by just over 4 points. The Right is at structural disadvantage because of the True Cons policy agenda. It is too far from the Center on everything from taxes to student loan debt to health care to the environment.