I think it all boils down to this.
The Republican Candidate will be Trump.
The Election will be decided on whether you're pro Trump or anti Trump.
It doesn't matter who the Democratic Candidate is.
If you're a Trump supporter, you'll vote for him regardless.
If you're not, then even if the Democratic Candidate is Kim Kardashian, you'll still give her you're vote over Trump.
I think the biggest boost to Trump's 2024 campaign has been the absolute shit show that is the Biden administration.