If Biden is running in 2024, if he makes it there, he is going to be fucking destroyed.
Even without putting the candidates in to question (It's Trump, barring something unexpected), he will barely be sentient by 2024. And he won't have the Coof to hide it, or maybe he'll try, which makes the situation even more sad.
Also, something I'd like to call "The Grand Illusion" will be permanently dead to a vast majority of persuadable voters, where repeating "TRUMP IS HITLER, TRUMP IS WHY YOUR LIFE IS HORRIBLE" ad nauseum will not matter because Trump isn't in power, and Biden has fucked up amazingly. His promise to "bring back normalcy" was a lie ( or the truth, its just that normalcy was dogshit), and people will put the blame on him and vote against him, just like Obama's second run. And since his margins of "victory" were small, he is going to turn the map red as hell as Independents swing right hard. By 2024, you would also have potentially Republican governors in swing states like PA, WI, and MI due to 2022, causing there to be no behind the scenes "fortification."
I really don't know why Biden is running again, nor do I think he will last that long, but it makes 2024 easier for the meantime.