Biden absolutely has some control over this, but Netanyahu is the bigger problem at the moment. Biden has influence over Netanyahu (with a lot of caveats and red tape due to decades of foreign policy), and Harris has influence over Biden....but that's not the same thing as absolute control. There are also parts of this that have to get approved by congress and there's only so much the office of the president can do unilaterally.
They can be doing more, and they should be doing more, but Harris' role and capability is limited to that of an advisor (under strict scrutiny from everyone) right now, and that doesn't actually give her that much power.
We have 3 cats, and unintentionally, they are all long haired cats. They were the ones that picked us, and we weren't about to tell them they were wrong and adopt a different cat because of their hair length.