I never thought Biden would actually be the nominee. They won't nominate Sanders because he is not a democrat.
Someone will emerge at the convention. Don't know who it will be. I also think the democrats are concentrating their efforts on increasing their control of the House and taking control of the Senate. If they are successful it wont really matter who is president. If Trump is re-elected all he would have is the power of the veto and there are enough RINOs to override his veto on some issues.
In 2024 the democrats will most likely win the White House based on past elections.