...Joe Biden.
IMHO, the Dems should've just went with Biden. Even though the 2020 election was rigged, Biden can at least die believing that he was the only one who beat Trump. And the Dems might be wondering if Biden could cheat ahem beat Trump again. The people might not be suspicious of a Biden victory since he is the sitting president.
The Dems got their karma for rigging 2020 and for ousting Biden at the last minute. What an embarrassment for the Dems for kicking their own president to the curb only to lose to the man they despise.