I don't know about Democrats in general, but Biden in particular isn't going to have much of an advantage at all if he somehow is still around to run for re-election in 2024. I mean, they're likely going to 25th him out in favor of Kamala Harris instead, and she will have her own massive pile of problems, but by election season 2024 Biden will be fit for hospice care,(he is now, but even more so.)not running for political office.
There's only so much dementia medication and stimulants can do to prop up someone who's got one foot on a banana peel, metaphorically speaking. The Dems had better hope they can drum up a convincing enough excuse to justify not having Biden at any debates, because if they can't, he may wind up going full alzheimers on national tv, and before anyone brings this up, there are practical limits to electoral fraud too. If HR1 is defeated like I suspect it will be, the Dems aren't going to be able to pull the shit they pulled in 2020.