That would be a veritable nightmare, wouldn't it?
But I have a hunch that history won't repeat itself this year. The Party in the WH typically loses Congress in the midterms, but even before the batshit crazy pro-theocracy rulings from SCOTUS I felt Democrats would not only keep control but add seats, as well. If enough voters learn about the "unknown" side-effects, consequences of the decisions the more likely it is that Republicans not only don't win control of Congress but lose seats. Manchin & Simena are water carriers for the Republicans, so we'd need at least two to three more Dem Senators to take away their veto power in the Senate and I believe that is not out of reach.
In generic polls (which mean nothing at this point, if they ever do) show Biden favored over Trump by a comfortable margin, Biden vs. Desantis, not so good.
I agree Biden should step aside in the 2024 race, but Kamala simply isn't likable enough or well-known enough to take 270 electoral votes against the smarm that is Desantis, although she could possibly beat Trump. Possibly. The Democratic Party does need to field some younger candidates but not reject the advantage of experience- a young Progressive with an older Left-leaning Centrist as VP?