Honestly, the Democratic base is divided on the issue, the Republican one is united. So the only thing Biden and Harris can do until election is lip service : Promising to protect Israel and at the same time making noises about humanitarian rights having to be respected. And otherwise do as little as possible to make people pay attention to the conflict.
But not only did Israel everything in its power to let the Republicans win, Netanyahu has repeatedly snubbed and humiliated Biden and sabotaged his policies all the time. I am not sure what Biden would want to do without the election looming.
I am not saying it is guaranteed that he will follow through, but there is certainly a possibility.
I don't buy that it is only an election promise. Most possible voter, including most undecided want the US to support Israel unconditionally.