Trump didn't create the idea. Israel leadership do not hide that they want the whole land and want paledtinian to go to Egypt. Do you really think that biden didn't know about the plan? He is the guy who said if there was no Israel we had to create an Israel.
The Biden Administration has been in full support of Israels actions. Any statements to the contrary remained statements and any "actions" taken against Israel, such as not sending 2.000 pound bombs, but everything below that, the infamous "aid"-pier that was ultimately used as a beachhead for an Israeli murder incursion disguised as humanitarian aid trucks, or the "ultimatum" without any consequences prior to the elections were solely smokescreens.
Everything the Biden Administration said was merely to create an appearance of discontent. However the actions of the Biden Administration are those of full support for the genocide against the Palestinians and the violent expansion of a "greater" Israel.
It's no surprise that Trump has and will continue to embolden Israel more.
Still, the fact that Trump pressured Israel to start the ceasefire in Gaza is incredibly frustrating because the Biden admin could have done the same thing for over an entire year and chose not too. At the expense of both the lives of Palestinians and the Democrats chance of reelection