As the commander in chief he already has the power to stop arms transfers. Full stop. This is legally justified by laws on the books that America cannot be complicit in genocide, which is clearly what’s happening in Gaza.
With America applying pressure and cooperating with the UN, peacekeeping troops could be on the ground in a matter of days to prevent further civilian casualties and ensure an end to the famine. Bibi is a genocidal maniac, but I’m not sure he’d risk slaughtering NATO troops, as that’s quite a step beyond aid workers.
So yeah, Biden single handedly does have the power to end this bloodshed. Will he? Hell no. Biden has proven many times throughout his career he is an extreme Zionist. He’s on Bibi’s side, which is why the US state dept is going to such great lengths to provide Israel cover.