“A brokered convention occurs when a party's nominee is not selected by a majority in the first round of delegate voting at the party's nominating convention.
Most delegates are then permitted to vote for whichever candidate they choose”
Kamala Harris who can access the funds in the Biden/Harris campaign war chest because her name is already on the ticket. Anyone else would have to start from $0.
Dems are as tied to Biden as nominee as Republicans are to DJT; no viable alternative candidate ran in either primary. Since neither is not going to step aside under any circumstances, the only wrinkle is if either of them becomes incapacitated; then it's basically chaos until election day.
It's not gonna work unless Biden voluntarily steps down and chooses someone. Kamala would be the only choice but she has as bad if not worse favorable levels than Biden.