They need Kamala as the 51st Senate Vote.
I doubt that means anything. They can simply coerce a few Republic squishes to go along with them in a tight vote.
Harris is disposable if she won't play along with the others. And it appears that she won't.
Votes in the Senate are all theatrical productions anyway. The real deals are made in closed-door conference rooms. It's all about who gets what share of the loot. Both parties are in on the theft, and nobody wants to spoil the setup.