Speculation is encouraged with some rational support.
Biden hoped to move foreign policy emphasis away from the Arab-Israeli conflict to China and Russia, because his Democrat predecessors have always had trouble dealing with that conflict; mostly because the support is for the aggressor side. I have presented the argument that David purchased the the threshing floor of King Arauna, the Jebusite [a descendent of Ishmael, therefore, an Arab in modern jargon], and the surrounding land, now called the West Bank. No one has purchased it since. Some argue that military possession of another's land is legitimate. Fine. descendants of Ishmael occupied that land that is now called Palestine upon the departure of many, but probably not all of the tribes of the House of Israel during the famine crisis, led by Jacob [Israel] into Egypt. When the House of Israel returned some 400 years later, they took it back. When the House of Israel was decimated by Babylon [historic Arabs] in 600 BC, the Arabs took it back, and so on over the millennia since, including, by the way, the re-occupation of the West Bank and Gaza by the modern nation of Israel in 1967, and they have occupied it since [legitimately, by the original purchase, and by military occupation, which opponents of Israel maintain has been the legitimacy of the Arab possession of the land].
So, whose occupation is legitimate? The last guy to do ity, that's who. And the last guy was the one who bought it in the first place, and no one has bothered to do that since.
But Biden making deals with the guy who says "Death to Israel" kind of reveals his hand in the matter, and it does not support Israel, does it? Is that rational reasoning in your book, or not, that he opposes a united Israel with its capital being the site of the US Embassy?