For me the worst thing is the GOP SCOTUS justices. The justices are toxic and their power must be curbed and that pro-Trump immunity thing overturn. Plus - the only way to restore reproductive rights is radical action on the court - packing it or whatever. Of course - if Biden somehow manages to get a second term and by some miracle stays in office the whole time - there's a zero percent chance he'll do anything at all.
As others have said in this thread the worship of American civic religion and voting means libs will keep lecturing the public to vote and keep ignoring the fact that the only way the GOP justices can be stopped is by DC dems doing something. If Biden gets a second term and he is forced to give the presidency to Kamala (or he dies and she gets it anyway) - I guess there's a tiny percent chance she might do something.
In fact - weird as it is - if Biden has one or two "bad days" like at the debate - libs might actually argue that voting for Biden is also voting for Kamala just in case, erm, Biden can't finish his term. And, look, maybe she'll do something about the court.
She won't and they know it but they'll lie to the public and perhaps even themselves too. Worship of American civic religion and voting is a hell of drug.

If the dem machine was smart - they would have been kissing her ass and maintaining a subtle relationship with her even before the election in 2020. If your candidate is a super-old, angry, stubborn person - planning ahead about how to change the situation is wise. If you plan ahead - sucking up can pay dividends. This is not complicated at all.
But I assume the machine is filled with abject morons so they didn't do that. If I'm right - they have no cards to play other than begging and pleading which nearly always tends to be a big loser. Another "bad day" and Jill and her hubby might start to worry about his all important legacy. And the dem machine can play on that.
If the number of people in DC and boldface name dems start asking him to drop out gets to be too big and/or the number grows too fast - that's entwined with legacy too and is a another pressure to drop out. I have no idea what "too big" or "too fast" is. Newsom and Whitmer are local party soldiers focused on 2028.
They won't ask him to drop out unless they know for certain he's already a dead man walking. If the say they have "losing confidence" in him that's surely a sign Biden is toast and he can't remain the nominee.
Whatever happens - this month and next month will be fascinating.