There will be no contested convention. The RINO-progressive Deep State apparatus will guarantee it won't happen. Bernie Bros won't be as pissed this time around, despite the Project Veritas tapes, especially once the VP selection will be a communist on steroids.
Let's play along for a second. If a Biden/Omar ticket should somehow win, then Biden will be resigning the last week of January 2022, and President Omar will be giving that year's State of the Union. The week is selected so that his successor will be able to run in two, not just one, relection terms, and still have the advantage of incumbency of almost two year. She will then bring on a caretaker VP, perhaps a vulnerable senator from a state controlled by a Dem governor and legislature (one that guarantees a communist Dem replacement that can then be given the incumbent advantage at the next election) until 2024, after which Omar will then select
Speaker AOC as her permanent VP.