I'm not American so everything I say is both completely detached from the situation (albeit not emotionally) and entirely lacking anecdotal experience. Nothing new to relate, either — just adding my tuppence to the pile.
Biden seems absolutely radioactive at this point and it is deeply sad to watch the party apparatus speak anonymously while feign enthusiasm in public. It's extremely transparent and will come back to bite all of them. I honestly see no way for him to regain lost ground. It's so weird the way this is playing out, in the UK we'd have yeeted our leader in a matter of hours after a showing like that debate, esp with the years of context and warning signs that fed into it.
None of those subsequent appearances; NATO summit; Morning Joe; the ABC interview or that one where he called himself the first black woman president, are realistically doing aaaanything meaningful to convince people otherwise. It's like being browbeaten into submission, "don't believe your lying eyes", and that is far more of a winning quality among the GOP base. For anybody else, it just triggers revulsion.
Give the nomination to Kamala, and bring in somebody even younger than her for the Veep who can communicate well. I'd rather take my chances on that than hope Biden's rapidly sinking ship can make it to land before it goes under. I understand that some think they're better off sticking with Biden based on polling/incumbency advantage but I really do think Biden has hit his ceiling, people desperately want change, and simply putting younger, fresher faces on the ticket will go a long way to achieving that.
They just need to go on an absolute campaigning blitz between now and November so that everybody knows exactly what they stand for and what distinguishes them from Trump and Biden alike. It's not a guaranteed win by any means, but it's better than an all-but-certain defeat.